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Commit | Line | Data |
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1b1a35ee XL |
1 | #[cfg(test)] |
2 | mod tests; | |
3 | ||
4 | use hashbrown::hash_set as base; | |
5 | ||
532ac7d7 | 6 | use crate::borrow::Borrow; |
e1599b0c | 7 | use crate::collections::TryReserveError; |
532ac7d7 | 8 | use crate::fmt; |
dfeec247 | 9 | use crate::hash::{BuildHasher, Hash}; |
04454e1e | 10 | use crate::iter::{Chain, FusedIterator}; |
dfeec247 | 11 | use crate::ops::{BitAnd, BitOr, BitXor, Sub}; |
1a4d82fc | 12 | |
1b1a35ee | 13 | use super::map::{map_try_reserve_error, RandomState}; |
1a4d82fc JJ |
14 | |
15 | // Future Optimization (FIXME!) | |
532ac7d7 | 16 | // ============================ |
1a4d82fc JJ |
17 | // |
18 | // Iteration over zero sized values is a noop. There is no need | |
19 | // for `bucket.val` in the case of HashSet. I suppose we would need HKT | |
20 | // to get rid of it properly. | |
21 | ||
6a06907d | 22 | /// A [hash set] implemented as a `HashMap` where the value is `()`. |
d9579d0f | 23 | /// |
cc61c64b XL |
24 | /// As with the [`HashMap`] type, a `HashSet` requires that the elements |
25 | /// implement the [`Eq`] and [`Hash`] traits. This can frequently be achieved by | |
d9579d0f AL |
26 | /// using `#[derive(PartialEq, Eq, Hash)]`. If you implement these yourself, |
27 | /// it is important that the following property holds: | |
c34b1796 AL |
28 | /// |
29 | /// ```text | |
30 | /// k1 == k2 -> hash(k1) == hash(k2) | |
31 | /// ``` | |
32 | /// | |
33 | /// In other words, if two keys are equal, their hashes must be equal. | |
1a4d82fc | 34 | /// |
c34b1796 | 35 | /// |
923072b8 FG |
36 | /// It is a logic error for a key to be modified in such a way that the key's |
37 | /// hash, as determined by the [`Hash`] trait, or its equality, as determined by | |
38 | /// the [`Eq`] trait, changes while it is in the map. This is normally only | |
39 | /// possible through [`Cell`], [`RefCell`], global state, I/O, or unsafe code. | |
40 | /// The behavior resulting from such a logic error is not specified, but will | |
41 | /// be encapsulated to the `HashSet` that observed the logic error and not | |
42 | /// result in undefined behavior. This could include panics, incorrect results, | |
43 | /// aborts, memory leaks, and non-termination. | |
c34b1796 AL |
44 | /// |
45 | /// # Examples | |
1a4d82fc JJ |
46 | /// |
47 | /// ``` | |
48 | /// use std::collections::HashSet; | |
49 | /// // Type inference lets us omit an explicit type signature (which | |
94b46f34 | 50 | /// // would be `HashSet<String>` in this example). |
1a4d82fc JJ |
51 | /// let mut books = HashSet::new(); |
52 | /// | |
53 | /// // Add some books. | |
94b46f34 XL |
54 | /// books.insert("A Dance With Dragons".to_string()); |
55 | /// books.insert("To Kill a Mockingbird".to_string()); | |
56 | /// books.insert("The Odyssey".to_string()); | |
57 | /// books.insert("The Great Gatsby".to_string()); | |
1a4d82fc JJ |
58 | /// |
59 | /// // Check for a specific one. | |
d9579d0f | 60 | /// if !books.contains("The Winds of Winter") { |
1a4d82fc JJ |
61 | /// println!("We have {} books, but The Winds of Winter ain't one.", |
62 | /// books.len()); | |
63 | /// } | |
64 | /// | |
65 | /// // Remove a book. | |
d9579d0f | 66 | /// books.remove("The Odyssey"); |
1a4d82fc JJ |
67 | /// |
68 | /// // Iterate over everything. | |
d9579d0f | 69 | /// for book in &books { |
5e7ed085 | 70 | /// println!("{book}"); |
1a4d82fc JJ |
71 | /// } |
72 | /// ``` | |
73 | /// | |
74 | /// The easiest way to use `HashSet` with a custom type is to derive | |
cc61c64b XL |
75 | /// [`Eq`] and [`Hash`]. We must also derive [`PartialEq`], this will in the |
76 | /// future be implied by [`Eq`]. | |
1a4d82fc JJ |
77 | /// |
78 | /// ``` | |
79 | /// use std::collections::HashSet; | |
85aaf69f | 80 | /// #[derive(Hash, Eq, PartialEq, Debug)] |
94b46f34 XL |
81 | /// struct Viking { |
82 | /// name: String, | |
85aaf69f | 83 | /// power: usize, |
1a4d82fc JJ |
84 | /// } |
85 | /// | |
86 | /// let mut vikings = HashSet::new(); | |
87 | /// | |
94b46f34 XL |
88 | /// vikings.insert(Viking { name: "Einar".to_string(), power: 9 }); |
89 | /// vikings.insert(Viking { name: "Einar".to_string(), power: 9 }); | |
90 | /// vikings.insert(Viking { name: "Olaf".to_string(), power: 4 }); | |
91 | /// vikings.insert(Viking { name: "Harald".to_string(), power: 8 }); | |
1a4d82fc JJ |
92 | /// |
93 | /// // Use derived implementation to print the vikings. | |
d9579d0f | 94 | /// for x in &vikings { |
5e7ed085 | 95 | /// println!("{x:?}"); |
1a4d82fc JJ |
96 | /// } |
97 | /// ``` | |
c30ab7b3 | 98 | /// |
94222f64 | 99 | /// A `HashSet` with a known list of items can be initialized from an array: |
c30ab7b3 SL |
100 | /// |
101 | /// ``` | |
102 | /// use std::collections::HashSet; | |
103 | /// | |
94222f64 | 104 | /// let viking_names = HashSet::from(["Einar", "Olaf", "Harald"]); |
c30ab7b3 | 105 | /// ``` |
cc61c64b | 106 | /// |
6a06907d | 107 | /// [hash set]: crate::collections#use-the-set-variant-of-any-of-these-maps-when |
1b1a35ee | 108 | /// [`HashMap`]: crate::collections::HashMap |
3dfed10e XL |
109 | /// [`RefCell`]: crate::cell::RefCell |
110 | /// [`Cell`]: crate::cell::Cell | |
c295e0f8 | 111 | #[cfg_attr(not(test), rustc_diagnostic_item = "HashSet")] |
85aaf69f | 112 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 113 | pub struct HashSet<T, S = RandomState> { |
1b1a35ee | 114 | base: base::HashSet<T, S>, |
1a4d82fc JJ |
115 | } |
116 | ||
74b04a01 | 117 | impl<T> HashSet<T, RandomState> { |
3b2f2976 | 118 | /// Creates an empty `HashSet`. |
1a4d82fc | 119 | /// |
ea8adc8c XL |
120 | /// The hash set is initially created with a capacity of 0, so it will not allocate until it |
121 | /// is first inserted into. | |
122 | /// | |
c34b1796 | 123 | /// # Examples |
1a4d82fc JJ |
124 | /// |
125 | /// ``` | |
126 | /// use std::collections::HashSet; | |
3b2f2976 | 127 | /// let set: HashSet<i32> = HashSet::new(); |
1a4d82fc JJ |
128 | /// ``` |
129 | #[inline] | |
c295e0f8 | 130 | #[must_use] |
85aaf69f | 131 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 132 | pub fn new() -> HashSet<T, RandomState> { |
1b1a35ee | 133 | Default::default() |
1a4d82fc JJ |
134 | } |
135 | ||
923072b8 | 136 | /// Creates an empty `HashSet` with at least the specified capacity. |
c30ab7b3 SL |
137 | /// |
138 | /// The hash set will be able to hold at least `capacity` elements without | |
923072b8 FG |
139 | /// reallocating. This method is allowed to allocate for more elements than |
140 | /// `capacity`. If `capacity` is 0, the hash set will not allocate. | |
1a4d82fc | 141 | /// |
c34b1796 | 142 | /// # Examples |
1a4d82fc JJ |
143 | /// |
144 | /// ``` | |
145 | /// use std::collections::HashSet; | |
3b2f2976 XL |
146 | /// let set: HashSet<i32> = HashSet::with_capacity(10); |
147 | /// assert!(set.capacity() >= 10); | |
1a4d82fc JJ |
148 | /// ``` |
149 | #[inline] | |
c295e0f8 | 150 | #[must_use] |
85aaf69f SL |
151 | #[stable(feature = "rust1", since = "1.0.0")] |
152 | pub fn with_capacity(capacity: usize) -> HashSet<T, RandomState> { | |
1b1a35ee | 153 | HashSet { base: base::HashSet::with_capacity_and_hasher(capacity, Default::default()) } |
1a4d82fc JJ |
154 | } |
155 | } | |
156 | ||
9fa01778 XL |
157 | impl<T, S> HashSet<T, S> { |
158 | /// Returns the number of elements the set can hold without reallocating. | |
159 | /// | |
160 | /// # Examples | |
161 | /// | |
162 | /// ``` | |
163 | /// use std::collections::HashSet; | |
164 | /// let set: HashSet<i32> = HashSet::with_capacity(100); | |
165 | /// assert!(set.capacity() >= 100); | |
166 | /// ``` | |
167 | #[inline] | |
168 | #[stable(feature = "rust1", since = "1.0.0")] | |
169 | pub fn capacity(&self) -> usize { | |
1b1a35ee | 170 | self.base.capacity() |
9fa01778 XL |
171 | } |
172 | ||
173 | /// An iterator visiting all elements in arbitrary order. | |
174 | /// The iterator element type is `&'a T`. | |
175 | /// | |
176 | /// # Examples | |
177 | /// | |
178 | /// ``` | |
179 | /// use std::collections::HashSet; | |
180 | /// let mut set = HashSet::new(); | |
181 | /// set.insert("a"); | |
182 | /// set.insert("b"); | |
183 | /// | |
184 | /// // Will print in an arbitrary order. | |
185 | /// for x in set.iter() { | |
5e7ed085 | 186 | /// println!("{x}"); |
9fa01778 XL |
187 | /// } |
188 | /// ``` | |
923072b8 FG |
189 | /// |
190 | /// # Performance | |
191 | /// | |
192 | /// In the current implementation, iterating over set takes O(capacity) time | |
193 | /// instead of O(len) because it internally visits empty buckets too. | |
48663c56 | 194 | #[inline] |
5e7ed085 | 195 | #[rustc_lint_query_instability] |
9fa01778 | 196 | #[stable(feature = "rust1", since = "1.0.0")] |
532ac7d7 | 197 | pub fn iter(&self) -> Iter<'_, T> { |
1b1a35ee | 198 | Iter { base: self.base.iter() } |
9fa01778 XL |
199 | } |
200 | ||
201 | /// Returns the number of elements in the set. | |
202 | /// | |
203 | /// # Examples | |
204 | /// | |
205 | /// ``` | |
206 | /// use std::collections::HashSet; | |
207 | /// | |
208 | /// let mut v = HashSet::new(); | |
209 | /// assert_eq!(v.len(), 0); | |
210 | /// v.insert(1); | |
211 | /// assert_eq!(v.len(), 1); | |
212 | /// ``` | |
48663c56 | 213 | #[inline] |
9fa01778 XL |
214 | #[stable(feature = "rust1", since = "1.0.0")] |
215 | pub fn len(&self) -> usize { | |
1b1a35ee | 216 | self.base.len() |
9fa01778 XL |
217 | } |
218 | ||
219 | /// Returns `true` if the set contains no elements. | |
220 | /// | |
221 | /// # Examples | |
222 | /// | |
223 | /// ``` | |
224 | /// use std::collections::HashSet; | |
225 | /// | |
226 | /// let mut v = HashSet::new(); | |
227 | /// assert!(v.is_empty()); | |
228 | /// v.insert(1); | |
229 | /// assert!(!v.is_empty()); | |
230 | /// ``` | |
48663c56 | 231 | #[inline] |
9fa01778 XL |
232 | #[stable(feature = "rust1", since = "1.0.0")] |
233 | pub fn is_empty(&self) -> bool { | |
1b1a35ee | 234 | self.base.is_empty() |
9fa01778 XL |
235 | } |
236 | ||
5099ac24 FG |
237 | /// Clears the set, returning all elements as an iterator. Keeps the |
238 | /// allocated memory for reuse. | |
239 | /// | |
240 | /// If the returned iterator is dropped before being fully consumed, it | |
241 | /// drops the remaining elements. The returned iterator keeps a mutable | |
242 | /// borrow on the vector to optimize its implementation. | |
9fa01778 XL |
243 | /// |
244 | /// # Examples | |
245 | /// | |
246 | /// ``` | |
247 | /// use std::collections::HashSet; | |
248 | /// | |
a2a8927a | 249 | /// let mut set = HashSet::from([1, 2, 3]); |
9fa01778 XL |
250 | /// assert!(!set.is_empty()); |
251 | /// | |
252 | /// // print 1, 2, 3 in an arbitrary order | |
253 | /// for i in set.drain() { | |
5e7ed085 | 254 | /// println!("{i}"); |
9fa01778 XL |
255 | /// } |
256 | /// | |
257 | /// assert!(set.is_empty()); | |
258 | /// ``` | |
259 | #[inline] | |
5e7ed085 | 260 | #[rustc_lint_query_instability] |
9fa01778 | 261 | #[stable(feature = "drain", since = "1.6.0")] |
532ac7d7 | 262 | pub fn drain(&mut self) -> Drain<'_, T> { |
1b1a35ee XL |
263 | Drain { base: self.base.drain() } |
264 | } | |
265 | ||
266 | /// Creates an iterator which uses a closure to determine if a value should be removed. | |
267 | /// | |
268 | /// If the closure returns true, then the value is removed and yielded. | |
269 | /// If the closure returns false, the value will remain in the list and will not be yielded | |
270 | /// by the iterator. | |
271 | /// | |
272 | /// If the iterator is only partially consumed or not consumed at all, each of the remaining | |
273 | /// values will still be subjected to the closure and removed and dropped if it returns true. | |
274 | /// | |
275 | /// It is unspecified how many more values will be subjected to the closure | |
276 | /// if a panic occurs in the closure, or if a panic occurs while dropping a value, or if the | |
277 | /// `DrainFilter` itself is leaked. | |
278 | /// | |
279 | /// # Examples | |
280 | /// | |
281 | /// Splitting a set into even and odd values, reusing the original set: | |
282 | /// | |
283 | /// ``` | |
284 | /// #![feature(hash_drain_filter)] | |
285 | /// use std::collections::HashSet; | |
286 | /// | |
287 | /// let mut set: HashSet<i32> = (0..8).collect(); | |
288 | /// let drained: HashSet<i32> = set.drain_filter(|v| v % 2 == 0).collect(); | |
289 | /// | |
290 | /// let mut evens = drained.into_iter().collect::<Vec<_>>(); | |
291 | /// let mut odds = set.into_iter().collect::<Vec<_>>(); | |
292 | /// evens.sort(); | |
293 | /// odds.sort(); | |
294 | /// | |
295 | /// assert_eq!(evens, vec![0, 2, 4, 6]); | |
296 | /// assert_eq!(odds, vec![1, 3, 5, 7]); | |
297 | /// ``` | |
298 | #[inline] | |
5e7ed085 | 299 | #[rustc_lint_query_instability] |
1b1a35ee XL |
300 | #[unstable(feature = "hash_drain_filter", issue = "59618")] |
301 | pub fn drain_filter<F>(&mut self, pred: F) -> DrainFilter<'_, T, F> | |
302 | where | |
303 | F: FnMut(&T) -> bool, | |
304 | { | |
305 | DrainFilter { base: self.base.drain_filter(pred) } | |
9fa01778 XL |
306 | } |
307 | ||
a2a8927a XL |
308 | /// Retains only the elements specified by the predicate. |
309 | /// | |
5e7ed085 | 310 | /// In other words, remove all elements `e` for which `f(&e)` returns `false`. |
a2a8927a XL |
311 | /// The elements are visited in unsorted (and unspecified) order. |
312 | /// | |
313 | /// # Examples | |
314 | /// | |
315 | /// ``` | |
316 | /// use std::collections::HashSet; | |
317 | /// | |
318 | /// let mut set = HashSet::from([1, 2, 3, 4, 5, 6]); | |
319 | /// set.retain(|&k| k % 2 == 0); | |
320 | /// assert_eq!(set.len(), 3); | |
321 | /// ``` | |
923072b8 FG |
322 | /// |
323 | /// # Performance | |
324 | /// | |
325 | /// In the current implementation, this operation takes O(capacity) time | |
326 | /// instead of O(len) because it internally visits empty buckets too. | |
5e7ed085 | 327 | #[rustc_lint_query_instability] |
a2a8927a XL |
328 | #[stable(feature = "retain_hash_collection", since = "1.18.0")] |
329 | pub fn retain<F>(&mut self, f: F) | |
330 | where | |
331 | F: FnMut(&T) -> bool, | |
332 | { | |
333 | self.base.retain(f) | |
334 | } | |
335 | ||
9fa01778 XL |
336 | /// Clears the set, removing all values. |
337 | /// | |
338 | /// # Examples | |
339 | /// | |
340 | /// ``` | |
341 | /// use std::collections::HashSet; | |
342 | /// | |
343 | /// let mut v = HashSet::new(); | |
344 | /// v.insert(1); | |
345 | /// v.clear(); | |
346 | /// assert!(v.is_empty()); | |
347 | /// ``` | |
48663c56 | 348 | #[inline] |
9fa01778 XL |
349 | #[stable(feature = "rust1", since = "1.0.0")] |
350 | pub fn clear(&mut self) { | |
1b1a35ee | 351 | self.base.clear() |
9fa01778 | 352 | } |
9fa01778 | 353 | |
1a4d82fc JJ |
354 | /// Creates a new empty hash set which will use the given hasher to hash |
355 | /// keys. | |
356 | /// | |
357 | /// The hash set is also created with the default initial capacity. | |
358 | /// | |
9cc50fc6 SL |
359 | /// Warning: `hasher` is normally randomly generated, and |
360 | /// is designed to allow `HashSet`s to be resistant to attacks that | |
361 | /// cause many collisions and very poor performance. Setting it | |
362 | /// manually using this function can expose a DoS attack vector. | |
363 | /// | |
f9f354fc XL |
364 | /// The `hash_builder` passed should implement the [`BuildHasher`] trait for |
365 | /// the HashMap to be useful, see its documentation for details. | |
366 | /// | |
c34b1796 | 367 | /// # Examples |
1a4d82fc JJ |
368 | /// |
369 | /// ``` | |
370 | /// use std::collections::HashSet; | |
371 | /// use std::collections::hash_map::RandomState; | |
372 | /// | |
373 | /// let s = RandomState::new(); | |
9cc50fc6 | 374 | /// let mut set = HashSet::with_hasher(s); |
85aaf69f | 375 | /// set.insert(2); |
1a4d82fc JJ |
376 | /// ``` |
377 | #[inline] | |
9cc50fc6 SL |
378 | #[stable(feature = "hashmap_build_hasher", since = "1.7.0")] |
379 | pub fn with_hasher(hasher: S) -> HashSet<T, S> { | |
1b1a35ee | 380 | HashSet { base: base::HashSet::with_hasher(hasher) } |
1a4d82fc JJ |
381 | } |
382 | ||
923072b8 | 383 | /// Creates an empty `HashSet` with at least the specified capacity, using |
c30ab7b3 SL |
384 | /// `hasher` to hash the keys. |
385 | /// | |
386 | /// The hash set will be able to hold at least `capacity` elements without | |
923072b8 FG |
387 | /// reallocating. This method is allowed to allocate for more elements than |
388 | /// `capacity`. If `capacity` is 0, the hash set will not allocate. | |
1a4d82fc JJ |
389 | /// |
390 | /// Warning: `hasher` is normally randomly generated, and | |
391 | /// is designed to allow `HashSet`s to be resistant to attacks that | |
392 | /// cause many collisions and very poor performance. Setting it | |
393 | /// manually using this function can expose a DoS attack vector. | |
394 | /// | |
f9f354fc XL |
395 | /// The `hash_builder` passed should implement the [`BuildHasher`] trait for |
396 | /// the HashMap to be useful, see its documentation for details. | |
397 | /// | |
c34b1796 | 398 | /// # Examples |
1a4d82fc JJ |
399 | /// |
400 | /// ``` | |
401 | /// use std::collections::HashSet; | |
402 | /// use std::collections::hash_map::RandomState; | |
403 | /// | |
404 | /// let s = RandomState::new(); | |
9cc50fc6 | 405 | /// let mut set = HashSet::with_capacity_and_hasher(10, s); |
85aaf69f | 406 | /// set.insert(1); |
1a4d82fc JJ |
407 | /// ``` |
408 | #[inline] | |
9cc50fc6 | 409 | #[stable(feature = "hashmap_build_hasher", since = "1.7.0")] |
c30ab7b3 | 410 | pub fn with_capacity_and_hasher(capacity: usize, hasher: S) -> HashSet<T, S> { |
1b1a35ee | 411 | HashSet { base: base::HashSet::with_capacity_and_hasher(capacity, hasher) } |
9cc50fc6 SL |
412 | } |
413 | ||
cc61c64b XL |
414 | /// Returns a reference to the set's [`BuildHasher`]. |
415 | /// | |
3b2f2976 XL |
416 | /// # Examples |
417 | /// | |
418 | /// ``` | |
419 | /// use std::collections::HashSet; | |
420 | /// use std::collections::hash_map::RandomState; | |
421 | /// | |
422 | /// let hasher = RandomState::new(); | |
423 | /// let set: HashSet<i32> = HashSet::with_hasher(hasher); | |
424 | /// let hasher: &RandomState = set.hasher(); | |
425 | /// ``` | |
48663c56 | 426 | #[inline] |
54a0048b | 427 | #[stable(feature = "hashmap_public_hasher", since = "1.9.0")] |
7453a54e | 428 | pub fn hasher(&self) -> &S { |
1b1a35ee | 429 | self.base.hasher() |
7453a54e | 430 | } |
74b04a01 | 431 | } |
7453a54e | 432 | |
74b04a01 XL |
433 | impl<T, S> HashSet<T, S> |
434 | where | |
435 | T: Eq + Hash, | |
436 | S: BuildHasher, | |
437 | { | |
1a4d82fc | 438 | /// Reserves capacity for at least `additional` more elements to be inserted |
923072b8 FG |
439 | /// in the `HashSet`. The collection may reserve more space to speculatively |
440 | /// avoid frequent reallocations. After calling `reserve`, | |
441 | /// capacity will be greater than or equal to `self.len() + additional`. | |
442 | /// Does nothing if capacity is already sufficient. | |
1a4d82fc JJ |
443 | /// |
444 | /// # Panics | |
445 | /// | |
85aaf69f | 446 | /// Panics if the new allocation size overflows `usize`. |
1a4d82fc | 447 | /// |
c34b1796 | 448 | /// # Examples |
1a4d82fc JJ |
449 | /// |
450 | /// ``` | |
451 | /// use std::collections::HashSet; | |
85aaf69f | 452 | /// let mut set: HashSet<i32> = HashSet::new(); |
1a4d82fc | 453 | /// set.reserve(10); |
3b2f2976 | 454 | /// assert!(set.capacity() >= 10); |
1a4d82fc | 455 | /// ``` |
48663c56 | 456 | #[inline] |
85aaf69f SL |
457 | #[stable(feature = "rust1", since = "1.0.0")] |
458 | pub fn reserve(&mut self, additional: usize) { | |
1b1a35ee | 459 | self.base.reserve(additional) |
1a4d82fc JJ |
460 | } |
461 | ||
48663c56 | 462 | /// Tries to reserve capacity for at least `additional` more elements to be inserted |
923072b8 FG |
463 | /// in the `HashSet`. The collection may reserve more space to speculatively |
464 | /// avoid frequent reallocations. After calling `reserve`, | |
465 | /// capacity will be greater than or equal to `self.len() + additional` if | |
466 | /// it returns `Ok(())`. | |
467 | /// Does nothing if capacity is already sufficient. | |
48663c56 XL |
468 | /// |
469 | /// # Errors | |
470 | /// | |
471 | /// If the capacity overflows, or the allocator reports a failure, then an error | |
472 | /// is returned. | |
473 | /// | |
474 | /// # Examples | |
475 | /// | |
476 | /// ``` | |
48663c56 XL |
477 | /// use std::collections::HashSet; |
478 | /// let mut set: HashSet<i32> = HashSet::new(); | |
923072b8 | 479 | /// set.try_reserve(10).expect("why is the test harness OOMing on a handful of bytes?"); |
48663c56 XL |
480 | /// ``` |
481 | #[inline] | |
c295e0f8 | 482 | #[stable(feature = "try_reserve", since = "1.57.0")] |
e1599b0c | 483 | pub fn try_reserve(&mut self, additional: usize) -> Result<(), TryReserveError> { |
1b1a35ee | 484 | self.base.try_reserve(additional).map_err(map_try_reserve_error) |
48663c56 XL |
485 | } |
486 | ||
1a4d82fc JJ |
487 | /// Shrinks the capacity of the set as much as possible. It will drop |
488 | /// down as much as possible while maintaining the internal rules | |
489 | /// and possibly leaving some space in accordance with the resize policy. | |
490 | /// | |
c34b1796 | 491 | /// # Examples |
1a4d82fc JJ |
492 | /// |
493 | /// ``` | |
494 | /// use std::collections::HashSet; | |
495 | /// | |
85aaf69f | 496 | /// let mut set = HashSet::with_capacity(100); |
1a4d82fc JJ |
497 | /// set.insert(1); |
498 | /// set.insert(2); | |
499 | /// assert!(set.capacity() >= 100); | |
500 | /// set.shrink_to_fit(); | |
501 | /// assert!(set.capacity() >= 2); | |
502 | /// ``` | |
48663c56 | 503 | #[inline] |
85aaf69f | 504 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 505 | pub fn shrink_to_fit(&mut self) { |
1b1a35ee | 506 | self.base.shrink_to_fit() |
1a4d82fc JJ |
507 | } |
508 | ||
0531ce1d XL |
509 | /// Shrinks the capacity of the set with a lower limit. It will drop |
510 | /// down no lower than the supplied limit while maintaining the internal rules | |
511 | /// and possibly leaving some space in accordance with the resize policy. | |
512 | /// | |
5869c6ff | 513 | /// If the current capacity is less than the lower limit, this is a no-op. |
0531ce1d XL |
514 | /// # Examples |
515 | /// | |
516 | /// ``` | |
0531ce1d XL |
517 | /// use std::collections::HashSet; |
518 | /// | |
519 | /// let mut set = HashSet::with_capacity(100); | |
520 | /// set.insert(1); | |
521 | /// set.insert(2); | |
522 | /// assert!(set.capacity() >= 100); | |
523 | /// set.shrink_to(10); | |
524 | /// assert!(set.capacity() >= 10); | |
525 | /// set.shrink_to(0); | |
526 | /// assert!(set.capacity() >= 2); | |
527 | /// ``` | |
528 | #[inline] | |
94222f64 | 529 | #[stable(feature = "shrink_to", since = "1.56.0")] |
0531ce1d | 530 | pub fn shrink_to(&mut self, min_capacity: usize) { |
1b1a35ee | 531 | self.base.shrink_to(min_capacity) |
0531ce1d XL |
532 | } |
533 | ||
cc61c64b | 534 | /// Visits the values representing the difference, |
0731742a | 535 | /// i.e., the values that are in `self` but not in `other`. |
1a4d82fc | 536 | /// |
c34b1796 | 537 | /// # Examples |
1a4d82fc JJ |
538 | /// |
539 | /// ``` | |
540 | /// use std::collections::HashSet; | |
a2a8927a XL |
541 | /// let a = HashSet::from([1, 2, 3]); |
542 | /// let b = HashSet::from([4, 2, 3, 4]); | |
1a4d82fc JJ |
543 | /// |
544 | /// // Can be seen as `a - b`. | |
545 | /// for x in a.difference(&b) { | |
5e7ed085 | 546 | /// println!("{x}"); // Print 1 |
1a4d82fc JJ |
547 | /// } |
548 | /// | |
3b2f2976 XL |
549 | /// let diff: HashSet<_> = a.difference(&b).collect(); |
550 | /// assert_eq!(diff, [1].iter().collect()); | |
1a4d82fc JJ |
551 | /// |
552 | /// // Note that difference is not symmetric, | |
553 | /// // and `b - a` means something else: | |
3b2f2976 XL |
554 | /// let diff: HashSet<_> = b.difference(&a).collect(); |
555 | /// assert_eq!(diff, [4].iter().collect()); | |
1a4d82fc | 556 | /// ``` |
48663c56 | 557 | #[inline] |
5e7ed085 | 558 | #[rustc_lint_query_instability] |
85aaf69f | 559 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 560 | pub fn difference<'a>(&'a self, other: &'a HashSet<T, S>) -> Difference<'a, T, S> { |
dfeec247 | 561 | Difference { iter: self.iter(), other } |
1a4d82fc JJ |
562 | } |
563 | ||
cc61c64b | 564 | /// Visits the values representing the symmetric difference, |
0731742a | 565 | /// i.e., the values that are in `self` or in `other` but not in both. |
1a4d82fc | 566 | /// |
c34b1796 | 567 | /// # Examples |
1a4d82fc JJ |
568 | /// |
569 | /// ``` | |
570 | /// use std::collections::HashSet; | |
a2a8927a XL |
571 | /// let a = HashSet::from([1, 2, 3]); |
572 | /// let b = HashSet::from([4, 2, 3, 4]); | |
1a4d82fc JJ |
573 | /// |
574 | /// // Print 1, 4 in arbitrary order. | |
575 | /// for x in a.symmetric_difference(&b) { | |
5e7ed085 | 576 | /// println!("{x}"); |
1a4d82fc JJ |
577 | /// } |
578 | /// | |
3b2f2976 XL |
579 | /// let diff1: HashSet<_> = a.symmetric_difference(&b).collect(); |
580 | /// let diff2: HashSet<_> = b.symmetric_difference(&a).collect(); | |
1a4d82fc JJ |
581 | /// |
582 | /// assert_eq!(diff1, diff2); | |
3b2f2976 | 583 | /// assert_eq!(diff1, [1, 4].iter().collect()); |
1a4d82fc | 584 | /// ``` |
48663c56 | 585 | #[inline] |
5e7ed085 | 586 | #[rustc_lint_query_instability] |
85aaf69f | 587 | #[stable(feature = "rust1", since = "1.0.0")] |
dfeec247 XL |
588 | pub fn symmetric_difference<'a>( |
589 | &'a self, | |
590 | other: &'a HashSet<T, S>, | |
591 | ) -> SymmetricDifference<'a, T, S> { | |
1a4d82fc JJ |
592 | SymmetricDifference { iter: self.difference(other).chain(other.difference(self)) } |
593 | } | |
594 | ||
cc61c64b | 595 | /// Visits the values representing the intersection, |
0731742a | 596 | /// i.e., the values that are both in `self` and `other`. |
1a4d82fc | 597 | /// |
923072b8 FG |
598 | /// When an equal element is present in `self` and `other` |
599 | /// then the resulting `Intersection` may yield references to | |
600 | /// one or the other. This can be relevant if `T` contains fields which | |
601 | /// are not compared by its `Eq` implementation, and may hold different | |
602 | /// value between the two equal copies of `T` in the two sets. | |
603 | /// | |
c34b1796 | 604 | /// # Examples |
1a4d82fc JJ |
605 | /// |
606 | /// ``` | |
607 | /// use std::collections::HashSet; | |
a2a8927a XL |
608 | /// let a = HashSet::from([1, 2, 3]); |
609 | /// let b = HashSet::from([4, 2, 3, 4]); | |
1a4d82fc JJ |
610 | /// |
611 | /// // Print 2, 3 in arbitrary order. | |
612 | /// for x in a.intersection(&b) { | |
5e7ed085 | 613 | /// println!("{x}"); |
1a4d82fc JJ |
614 | /// } |
615 | /// | |
3b2f2976 XL |
616 | /// let intersection: HashSet<_> = a.intersection(&b).collect(); |
617 | /// assert_eq!(intersection, [2, 3].iter().collect()); | |
1a4d82fc | 618 | /// ``` |
48663c56 | 619 | #[inline] |
5e7ed085 | 620 | #[rustc_lint_query_instability] |
85aaf69f | 621 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 622 | pub fn intersection<'a>(&'a self, other: &'a HashSet<T, S>) -> Intersection<'a, T, S> { |
0731742a | 623 | if self.len() <= other.len() { |
dfeec247 | 624 | Intersection { iter: self.iter(), other } |
0731742a | 625 | } else { |
dfeec247 | 626 | Intersection { iter: other.iter(), other: self } |
1a4d82fc JJ |
627 | } |
628 | } | |
629 | ||
cc61c64b | 630 | /// Visits the values representing the union, |
0731742a | 631 | /// i.e., all the values in `self` or `other`, without duplicates. |
1a4d82fc | 632 | /// |
c34b1796 | 633 | /// # Examples |
1a4d82fc JJ |
634 | /// |
635 | /// ``` | |
636 | /// use std::collections::HashSet; | |
a2a8927a XL |
637 | /// let a = HashSet::from([1, 2, 3]); |
638 | /// let b = HashSet::from([4, 2, 3, 4]); | |
1a4d82fc JJ |
639 | /// |
640 | /// // Print 1, 2, 3, 4 in arbitrary order. | |
641 | /// for x in a.union(&b) { | |
5e7ed085 | 642 | /// println!("{x}"); |
1a4d82fc JJ |
643 | /// } |
644 | /// | |
3b2f2976 XL |
645 | /// let union: HashSet<_> = a.union(&b).collect(); |
646 | /// assert_eq!(union, [1, 2, 3, 4].iter().collect()); | |
1a4d82fc | 647 | /// ``` |
48663c56 | 648 | #[inline] |
5e7ed085 | 649 | #[rustc_lint_query_instability] |
85aaf69f | 650 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 651 | pub fn union<'a>(&'a self, other: &'a HashSet<T, S>) -> Union<'a, T, S> { |
60c5eb7d | 652 | if self.len() >= other.len() { |
dfeec247 | 653 | Union { iter: self.iter().chain(other.difference(self)) } |
0731742a | 654 | } else { |
dfeec247 | 655 | Union { iter: other.iter().chain(self.difference(other)) } |
0731742a | 656 | } |
1a4d82fc JJ |
657 | } |
658 | ||
1a4d82fc JJ |
659 | /// Returns `true` if the set contains a value. |
660 | /// | |
661 | /// The value may be any borrowed form of the set's value type, but | |
cc61c64b | 662 | /// [`Hash`] and [`Eq`] on the borrowed form *must* match those for |
1a4d82fc JJ |
663 | /// the value type. |
664 | /// | |
c34b1796 | 665 | /// # Examples |
1a4d82fc JJ |
666 | /// |
667 | /// ``` | |
668 | /// use std::collections::HashSet; | |
669 | /// | |
a2a8927a | 670 | /// let set = HashSet::from([1, 2, 3]); |
1a4d82fc JJ |
671 | /// assert_eq!(set.contains(&1), true); |
672 | /// assert_eq!(set.contains(&4), false); | |
673 | /// ``` | |
48663c56 | 674 | #[inline] |
85aaf69f | 675 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 676 | pub fn contains<Q: ?Sized>(&self, value: &Q) -> bool |
dfeec247 XL |
677 | where |
678 | T: Borrow<Q>, | |
679 | Q: Hash + Eq, | |
1a4d82fc | 680 | { |
1b1a35ee | 681 | self.base.contains(value) |
1a4d82fc JJ |
682 | } |
683 | ||
e9174d1e SL |
684 | /// Returns a reference to the value in the set, if any, that is equal to the given value. |
685 | /// | |
686 | /// The value may be any borrowed form of the set's value type, but | |
cc61c64b | 687 | /// [`Hash`] and [`Eq`] on the borrowed form *must* match those for |
e9174d1e | 688 | /// the value type. |
cc61c64b | 689 | /// |
2c00a5a8 XL |
690 | /// # Examples |
691 | /// | |
692 | /// ``` | |
693 | /// use std::collections::HashSet; | |
694 | /// | |
a2a8927a | 695 | /// let set = HashSet::from([1, 2, 3]); |
2c00a5a8 XL |
696 | /// assert_eq!(set.get(&2), Some(&2)); |
697 | /// assert_eq!(set.get(&4), None); | |
698 | /// ``` | |
48663c56 | 699 | #[inline] |
54a0048b | 700 | #[stable(feature = "set_recovery", since = "1.9.0")] |
e9174d1e | 701 | pub fn get<Q: ?Sized>(&self, value: &Q) -> Option<&T> |
dfeec247 XL |
702 | where |
703 | T: Borrow<Q>, | |
704 | Q: Hash + Eq, | |
e9174d1e | 705 | { |
1b1a35ee | 706 | self.base.get(value) |
48663c56 XL |
707 | } |
708 | ||
709 | /// Inserts the given `value` into the set if it is not present, then | |
710 | /// returns a reference to the value in the set. | |
711 | /// | |
712 | /// # Examples | |
713 | /// | |
714 | /// ``` | |
715 | /// #![feature(hash_set_entry)] | |
716 | /// | |
717 | /// use std::collections::HashSet; | |
718 | /// | |
a2a8927a | 719 | /// let mut set = HashSet::from([1, 2, 3]); |
48663c56 XL |
720 | /// assert_eq!(set.len(), 3); |
721 | /// assert_eq!(set.get_or_insert(2), &2); | |
722 | /// assert_eq!(set.get_or_insert(100), &100); | |
723 | /// assert_eq!(set.len(), 4); // 100 was inserted | |
724 | /// ``` | |
725 | #[inline] | |
726 | #[unstable(feature = "hash_set_entry", issue = "60896")] | |
727 | pub fn get_or_insert(&mut self, value: T) -> &T { | |
728 | // Although the raw entry gives us `&mut T`, we only return `&T` to be consistent with | |
729 | // `get`. Key mutation is "raw" because you're not supposed to affect `Eq` or `Hash`. | |
1b1a35ee | 730 | self.base.get_or_insert(value) |
48663c56 XL |
731 | } |
732 | ||
dfeec247 XL |
733 | /// Inserts an owned copy of the given `value` into the set if it is not |
734 | /// present, then returns a reference to the value in the set. | |
735 | /// | |
736 | /// # Examples | |
737 | /// | |
738 | /// ``` | |
739 | /// #![feature(hash_set_entry)] | |
740 | /// | |
741 | /// use std::collections::HashSet; | |
742 | /// | |
743 | /// let mut set: HashSet<String> = ["cat", "dog", "horse"] | |
744 | /// .iter().map(|&pet| pet.to_owned()).collect(); | |
745 | /// | |
746 | /// assert_eq!(set.len(), 3); | |
747 | /// for &pet in &["cat", "dog", "fish"] { | |
748 | /// let value = set.get_or_insert_owned(pet); | |
749 | /// assert_eq!(value, pet); | |
750 | /// } | |
751 | /// assert_eq!(set.len(), 4); // a new "fish" was inserted | |
752 | /// ``` | |
753 | #[inline] | |
754 | #[unstable(feature = "hash_set_entry", issue = "60896")] | |
755 | pub fn get_or_insert_owned<Q: ?Sized>(&mut self, value: &Q) -> &T | |
756 | where | |
757 | T: Borrow<Q>, | |
758 | Q: Hash + Eq + ToOwned<Owned = T>, | |
759 | { | |
760 | // Although the raw entry gives us `&mut T`, we only return `&T` to be consistent with | |
761 | // `get`. Key mutation is "raw" because you're not supposed to affect `Eq` or `Hash`. | |
1b1a35ee | 762 | self.base.get_or_insert_owned(value) |
dfeec247 XL |
763 | } |
764 | ||
48663c56 XL |
765 | /// Inserts a value computed from `f` into the set if the given `value` is |
766 | /// not present, then returns a reference to the value in the set. | |
767 | /// | |
768 | /// # Examples | |
769 | /// | |
770 | /// ``` | |
771 | /// #![feature(hash_set_entry)] | |
772 | /// | |
773 | /// use std::collections::HashSet; | |
774 | /// | |
775 | /// let mut set: HashSet<String> = ["cat", "dog", "horse"] | |
776 | /// .iter().map(|&pet| pet.to_owned()).collect(); | |
777 | /// | |
778 | /// assert_eq!(set.len(), 3); | |
779 | /// for &pet in &["cat", "dog", "fish"] { | |
780 | /// let value = set.get_or_insert_with(pet, str::to_owned); | |
781 | /// assert_eq!(value, pet); | |
782 | /// } | |
783 | /// assert_eq!(set.len(), 4); // a new "fish" was inserted | |
784 | /// ``` | |
785 | #[inline] | |
786 | #[unstable(feature = "hash_set_entry", issue = "60896")] | |
787 | pub fn get_or_insert_with<Q: ?Sized, F>(&mut self, value: &Q, f: F) -> &T | |
dfeec247 XL |
788 | where |
789 | T: Borrow<Q>, | |
790 | Q: Hash + Eq, | |
791 | F: FnOnce(&Q) -> T, | |
48663c56 XL |
792 | { |
793 | // Although the raw entry gives us `&mut T`, we only return `&T` to be consistent with | |
794 | // `get`. Key mutation is "raw" because you're not supposed to affect `Eq` or `Hash`. | |
1b1a35ee | 795 | self.base.get_or_insert_with(value, f) |
e9174d1e SL |
796 | } |
797 | ||
8bb4bdeb | 798 | /// Returns `true` if `self` has no elements in common with `other`. |
1a4d82fc JJ |
799 | /// This is equivalent to checking for an empty intersection. |
800 | /// | |
c34b1796 | 801 | /// # Examples |
1a4d82fc JJ |
802 | /// |
803 | /// ``` | |
804 | /// use std::collections::HashSet; | |
805 | /// | |
a2a8927a | 806 | /// let a = HashSet::from([1, 2, 3]); |
85aaf69f | 807 | /// let mut b = HashSet::new(); |
1a4d82fc JJ |
808 | /// |
809 | /// assert_eq!(a.is_disjoint(&b), true); | |
810 | /// b.insert(4); | |
811 | /// assert_eq!(a.is_disjoint(&b), true); | |
812 | /// b.insert(1); | |
813 | /// assert_eq!(a.is_disjoint(&b), false); | |
814 | /// ``` | |
85aaf69f | 815 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 816 | pub fn is_disjoint(&self, other: &HashSet<T, S>) -> bool { |
0731742a XL |
817 | if self.len() <= other.len() { |
818 | self.iter().all(|v| !other.contains(v)) | |
819 | } else { | |
820 | other.iter().all(|v| !self.contains(v)) | |
821 | } | |
1a4d82fc JJ |
822 | } |
823 | ||
8bb4bdeb | 824 | /// Returns `true` if the set is a subset of another, |
0731742a | 825 | /// i.e., `other` contains at least all the values in `self`. |
1a4d82fc | 826 | /// |
c34b1796 | 827 | /// # Examples |
1a4d82fc JJ |
828 | /// |
829 | /// ``` | |
830 | /// use std::collections::HashSet; | |
831 | /// | |
a2a8927a | 832 | /// let sup = HashSet::from([1, 2, 3]); |
85aaf69f | 833 | /// let mut set = HashSet::new(); |
1a4d82fc JJ |
834 | /// |
835 | /// assert_eq!(set.is_subset(&sup), true); | |
836 | /// set.insert(2); | |
837 | /// assert_eq!(set.is_subset(&sup), true); | |
838 | /// set.insert(4); | |
839 | /// assert_eq!(set.is_subset(&sup), false); | |
840 | /// ``` | |
85aaf69f | 841 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 842 | pub fn is_subset(&self, other: &HashSet<T, S>) -> bool { |
dfeec247 | 843 | if self.len() <= other.len() { self.iter().all(|v| other.contains(v)) } else { false } |
1a4d82fc JJ |
844 | } |
845 | ||
8bb4bdeb | 846 | /// Returns `true` if the set is a superset of another, |
0731742a | 847 | /// i.e., `self` contains at least all the values in `other`. |
1a4d82fc | 848 | /// |
c34b1796 | 849 | /// # Examples |
1a4d82fc JJ |
850 | /// |
851 | /// ``` | |
852 | /// use std::collections::HashSet; | |
853 | /// | |
a2a8927a | 854 | /// let sub = HashSet::from([1, 2]); |
85aaf69f | 855 | /// let mut set = HashSet::new(); |
1a4d82fc JJ |
856 | /// |
857 | /// assert_eq!(set.is_superset(&sub), false); | |
858 | /// | |
859 | /// set.insert(0); | |
860 | /// set.insert(1); | |
861 | /// assert_eq!(set.is_superset(&sub), false); | |
862 | /// | |
863 | /// set.insert(2); | |
864 | /// assert_eq!(set.is_superset(&sub), true); | |
865 | /// ``` | |
866 | #[inline] | |
85aaf69f | 867 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
868 | pub fn is_superset(&self, other: &HashSet<T, S>) -> bool { |
869 | other.is_subset(self) | |
870 | } | |
871 | ||
b039eaaf SL |
872 | /// Adds a value to the set. |
873 | /// | |
923072b8 | 874 | /// Returns whether the value was newly inserted. That is: |
b039eaaf | 875 | /// |
923072b8 FG |
876 | /// - If the set did not previously contain this value, `true` is returned. |
877 | /// - If the set already contained this value, `false` is returned. | |
1a4d82fc | 878 | /// |
c34b1796 | 879 | /// # Examples |
1a4d82fc JJ |
880 | /// |
881 | /// ``` | |
882 | /// use std::collections::HashSet; | |
883 | /// | |
884 | /// let mut set = HashSet::new(); | |
885 | /// | |
85aaf69f | 886 | /// assert_eq!(set.insert(2), true); |
1a4d82fc JJ |
887 | /// assert_eq!(set.insert(2), false); |
888 | /// assert_eq!(set.len(), 1); | |
889 | /// ``` | |
48663c56 | 890 | #[inline] |
85aaf69f | 891 | #[stable(feature = "rust1", since = "1.0.0")] |
c30ab7b3 | 892 | pub fn insert(&mut self, value: T) -> bool { |
1b1a35ee | 893 | self.base.insert(value) |
c30ab7b3 | 894 | } |
1a4d82fc | 895 | |
e9174d1e SL |
896 | /// Adds a value to the set, replacing the existing value, if any, that is equal to the given |
897 | /// one. Returns the replaced value. | |
2c00a5a8 XL |
898 | /// |
899 | /// # Examples | |
900 | /// | |
901 | /// ``` | |
902 | /// use std::collections::HashSet; | |
903 | /// | |
904 | /// let mut set = HashSet::new(); | |
905 | /// set.insert(Vec::<i32>::new()); | |
906 | /// | |
907 | /// assert_eq!(set.get(&[][..]).unwrap().capacity(), 0); | |
908 | /// set.replace(Vec::with_capacity(10)); | |
909 | /// assert_eq!(set.get(&[][..]).unwrap().capacity(), 10); | |
910 | /// ``` | |
48663c56 | 911 | #[inline] |
54a0048b | 912 | #[stable(feature = "set_recovery", since = "1.9.0")] |
e9174d1e | 913 | pub fn replace(&mut self, value: T) -> Option<T> { |
1b1a35ee | 914 | self.base.replace(value) |
e9174d1e SL |
915 | } |
916 | ||
9fa01778 | 917 | /// Removes a value from the set. Returns whether the value was |
1a4d82fc JJ |
918 | /// present in the set. |
919 | /// | |
920 | /// The value may be any borrowed form of the set's value type, but | |
cc61c64b | 921 | /// [`Hash`] and [`Eq`] on the borrowed form *must* match those for |
1a4d82fc JJ |
922 | /// the value type. |
923 | /// | |
c34b1796 | 924 | /// # Examples |
1a4d82fc JJ |
925 | /// |
926 | /// ``` | |
927 | /// use std::collections::HashSet; | |
928 | /// | |
929 | /// let mut set = HashSet::new(); | |
930 | /// | |
85aaf69f | 931 | /// set.insert(2); |
1a4d82fc JJ |
932 | /// assert_eq!(set.remove(&2), true); |
933 | /// assert_eq!(set.remove(&2), false); | |
934 | /// ``` | |
48663c56 | 935 | #[inline] |
85aaf69f | 936 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 937 | pub fn remove<Q: ?Sized>(&mut self, value: &Q) -> bool |
dfeec247 XL |
938 | where |
939 | T: Borrow<Q>, | |
940 | Q: Hash + Eq, | |
1a4d82fc | 941 | { |
1b1a35ee | 942 | self.base.remove(value) |
1a4d82fc | 943 | } |
e9174d1e SL |
944 | |
945 | /// Removes and returns the value in the set, if any, that is equal to the given one. | |
946 | /// | |
947 | /// The value may be any borrowed form of the set's value type, but | |
cc61c64b | 948 | /// [`Hash`] and [`Eq`] on the borrowed form *must* match those for |
e9174d1e | 949 | /// the value type. |
cc61c64b | 950 | /// |
2c00a5a8 XL |
951 | /// # Examples |
952 | /// | |
953 | /// ``` | |
954 | /// use std::collections::HashSet; | |
955 | /// | |
a2a8927a | 956 | /// let mut set = HashSet::from([1, 2, 3]); |
2c00a5a8 XL |
957 | /// assert_eq!(set.take(&2), Some(2)); |
958 | /// assert_eq!(set.take(&2), None); | |
959 | /// ``` | |
48663c56 | 960 | #[inline] |
54a0048b | 961 | #[stable(feature = "set_recovery", since = "1.9.0")] |
e9174d1e | 962 | pub fn take<Q: ?Sized>(&mut self, value: &Q) -> Option<T> |
dfeec247 XL |
963 | where |
964 | T: Borrow<Q>, | |
965 | Q: Hash + Eq, | |
e9174d1e | 966 | { |
1b1a35ee | 967 | self.base.take(value) |
e9174d1e | 968 | } |
1a4d82fc JJ |
969 | } |
970 | ||
5869c6ff XL |
971 | #[stable(feature = "rust1", since = "1.0.0")] |
972 | impl<T, S> Clone for HashSet<T, S> | |
973 | where | |
974 | T: Clone, | |
975 | S: Clone, | |
976 | { | |
977 | #[inline] | |
978 | fn clone(&self) -> Self { | |
979 | Self { base: self.base.clone() } | |
980 | } | |
981 | ||
982 | #[inline] | |
983 | fn clone_from(&mut self, other: &Self) { | |
984 | self.base.clone_from(&other.base); | |
985 | } | |
986 | } | |
987 | ||
85aaf69f SL |
988 | #[stable(feature = "rust1", since = "1.0.0")] |
989 | impl<T, S> PartialEq for HashSet<T, S> | |
dfeec247 XL |
990 | where |
991 | T: Eq + Hash, | |
992 | S: BuildHasher, | |
1a4d82fc JJ |
993 | { |
994 | fn eq(&self, other: &HashSet<T, S>) -> bool { | |
c30ab7b3 SL |
995 | if self.len() != other.len() { |
996 | return false; | |
997 | } | |
1a4d82fc JJ |
998 | |
999 | self.iter().all(|key| other.contains(key)) | |
1000 | } | |
1001 | } | |
1002 | ||
85aaf69f SL |
1003 | #[stable(feature = "rust1", since = "1.0.0")] |
1004 | impl<T, S> Eq for HashSet<T, S> | |
dfeec247 XL |
1005 | where |
1006 | T: Eq + Hash, | |
1007 | S: BuildHasher, | |
c30ab7b3 SL |
1008 | { |
1009 | } | |
1a4d82fc | 1010 | |
85aaf69f SL |
1011 | #[stable(feature = "rust1", since = "1.0.0")] |
1012 | impl<T, S> fmt::Debug for HashSet<T, S> | |
dfeec247 | 1013 | where |
74b04a01 | 1014 | T: fmt::Debug, |
1a4d82fc | 1015 | { |
532ac7d7 | 1016 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
62682a34 | 1017 | f.debug_set().entries(self.iter()).finish() |
1a4d82fc JJ |
1018 | } |
1019 | } | |
1020 | ||
85aaf69f SL |
1021 | #[stable(feature = "rust1", since = "1.0.0")] |
1022 | impl<T, S> FromIterator<T> for HashSet<T, S> | |
dfeec247 XL |
1023 | where |
1024 | T: Eq + Hash, | |
1025 | S: BuildHasher + Default, | |
1a4d82fc | 1026 | { |
48663c56 | 1027 | #[inline] |
c30ab7b3 | 1028 | fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> HashSet<T, S> { |
476ff2be SL |
1029 | let mut set = HashSet::with_hasher(Default::default()); |
1030 | set.extend(iter); | |
1a4d82fc JJ |
1031 | set |
1032 | } | |
1033 | } | |
1034 | ||
94222f64 XL |
1035 | #[stable(feature = "std_collections_from_array", since = "1.56.0")] |
1036 | // Note: as what is currently the most convenient built-in way to construct | |
1037 | // a HashSet, a simple usage of this function must not *require* the user | |
1038 | // to provide a type annotation in order to infer the third type parameter | |
1039 | // (the hasher parameter, conventionally "S"). | |
1040 | // To that end, this impl is defined using RandomState as the concrete | |
1041 | // type of S, rather than being generic over `S: BuildHasher + Default`. | |
1042 | // It is expected that users who want to specify a hasher will manually use | |
1043 | // `with_capacity_and_hasher`. | |
1044 | // If type parameter defaults worked on impls, and if type parameter | |
1045 | // defaults could be mixed with const generics, then perhaps | |
1046 | // this could be generalized. | |
1047 | // See also the equivalent impl on HashMap. | |
1048 | impl<T, const N: usize> From<[T; N]> for HashSet<T, RandomState> | |
1049 | where | |
1050 | T: Eq + Hash, | |
1051 | { | |
1052 | /// # Examples | |
1053 | /// | |
1054 | /// ``` | |
1055 | /// use std::collections::HashSet; | |
1056 | /// | |
1057 | /// let set1 = HashSet::from([1, 2, 3, 4]); | |
1058 | /// let set2: HashSet<_> = [1, 2, 3, 4].into(); | |
1059 | /// assert_eq!(set1, set2); | |
1060 | /// ``` | |
1061 | fn from(arr: [T; N]) -> Self { | |
a2a8927a | 1062 | Self::from_iter(arr) |
94222f64 XL |
1063 | } |
1064 | } | |
1065 | ||
85aaf69f SL |
1066 | #[stable(feature = "rust1", since = "1.0.0")] |
1067 | impl<T, S> Extend<T> for HashSet<T, S> | |
dfeec247 XL |
1068 | where |
1069 | T: Eq + Hash, | |
1070 | S: BuildHasher, | |
1a4d82fc | 1071 | { |
48663c56 | 1072 | #[inline] |
c30ab7b3 | 1073 | fn extend<I: IntoIterator<Item = T>>(&mut self, iter: I) { |
1b1a35ee | 1074 | self.base.extend(iter); |
1a4d82fc | 1075 | } |
f9f354fc XL |
1076 | |
1077 | #[inline] | |
1078 | fn extend_one(&mut self, item: T) { | |
1b1a35ee | 1079 | self.base.insert(item); |
f9f354fc XL |
1080 | } |
1081 | ||
1082 | #[inline] | |
1083 | fn extend_reserve(&mut self, additional: usize) { | |
1b1a35ee | 1084 | self.base.extend_reserve(additional); |
f9f354fc | 1085 | } |
1a4d82fc JJ |
1086 | } |
1087 | ||
e9174d1e SL |
1088 | #[stable(feature = "hash_extend_copy", since = "1.4.0")] |
1089 | impl<'a, T, S> Extend<&'a T> for HashSet<T, S> | |
dfeec247 XL |
1090 | where |
1091 | T: 'a + Eq + Hash + Copy, | |
1092 | S: BuildHasher, | |
e9174d1e | 1093 | { |
48663c56 | 1094 | #[inline] |
c30ab7b3 | 1095 | fn extend<I: IntoIterator<Item = &'a T>>(&mut self, iter: I) { |
e9174d1e SL |
1096 | self.extend(iter.into_iter().cloned()); |
1097 | } | |
f9f354fc XL |
1098 | |
1099 | #[inline] | |
1100 | fn extend_one(&mut self, &item: &'a T) { | |
1b1a35ee | 1101 | self.base.insert(item); |
f9f354fc XL |
1102 | } |
1103 | ||
1104 | #[inline] | |
1105 | fn extend_reserve(&mut self, additional: usize) { | |
1106 | Extend::<T>::extend_reserve(self, additional) | |
1107 | } | |
e9174d1e SL |
1108 | } |
1109 | ||
85aaf69f SL |
1110 | #[stable(feature = "rust1", since = "1.0.0")] |
1111 | impl<T, S> Default for HashSet<T, S> | |
dfeec247 | 1112 | where |
74b04a01 | 1113 | S: Default, |
1a4d82fc | 1114 | { |
9e0c209e | 1115 | /// Creates an empty `HashSet<T, S>` with the `Default` value for the hasher. |
48663c56 | 1116 | #[inline] |
1a4d82fc | 1117 | fn default() -> HashSet<T, S> { |
1b1a35ee | 1118 | HashSet { base: Default::default() } |
1a4d82fc JJ |
1119 | } |
1120 | } | |
1121 | ||
85aaf69f | 1122 | #[stable(feature = "rust1", since = "1.0.0")] |
532ac7d7 | 1123 | impl<T, S> BitOr<&HashSet<T, S>> for &HashSet<T, S> |
dfeec247 XL |
1124 | where |
1125 | T: Eq + Hash + Clone, | |
1126 | S: BuildHasher + Default, | |
1a4d82fc JJ |
1127 | { |
1128 | type Output = HashSet<T, S>; | |
1129 | ||
1130 | /// Returns the union of `self` and `rhs` as a new `HashSet<T, S>`. | |
1131 | /// | |
1132 | /// # Examples | |
1133 | /// | |
1134 | /// ``` | |
1135 | /// use std::collections::HashSet; | |
1136 | /// | |
a2a8927a XL |
1137 | /// let a = HashSet::from([1, 2, 3]); |
1138 | /// let b = HashSet::from([3, 4, 5]); | |
1a4d82fc | 1139 | /// |
85aaf69f | 1140 | /// let set = &a | &b; |
1a4d82fc JJ |
1141 | /// |
1142 | /// let mut i = 0; | |
1143 | /// let expected = [1, 2, 3, 4, 5]; | |
62682a34 | 1144 | /// for x in &set { |
1a4d82fc JJ |
1145 | /// assert!(expected.contains(x)); |
1146 | /// i += 1; | |
1147 | /// } | |
1148 | /// assert_eq!(i, expected.len()); | |
1149 | /// ``` | |
1150 | fn bitor(self, rhs: &HashSet<T, S>) -> HashSet<T, S> { | |
1151 | self.union(rhs).cloned().collect() | |
1152 | } | |
1153 | } | |
1154 | ||
85aaf69f | 1155 | #[stable(feature = "rust1", since = "1.0.0")] |
532ac7d7 | 1156 | impl<T, S> BitAnd<&HashSet<T, S>> for &HashSet<T, S> |
dfeec247 XL |
1157 | where |
1158 | T: Eq + Hash + Clone, | |
1159 | S: BuildHasher + Default, | |
1a4d82fc JJ |
1160 | { |
1161 | type Output = HashSet<T, S>; | |
1162 | ||
1163 | /// Returns the intersection of `self` and `rhs` as a new `HashSet<T, S>`. | |
1164 | /// | |
1165 | /// # Examples | |
1166 | /// | |
1167 | /// ``` | |
1168 | /// use std::collections::HashSet; | |
1169 | /// | |
a2a8927a XL |
1170 | /// let a = HashSet::from([1, 2, 3]); |
1171 | /// let b = HashSet::from([2, 3, 4]); | |
1a4d82fc | 1172 | /// |
85aaf69f | 1173 | /// let set = &a & &b; |
1a4d82fc JJ |
1174 | /// |
1175 | /// let mut i = 0; | |
1176 | /// let expected = [2, 3]; | |
62682a34 | 1177 | /// for x in &set { |
1a4d82fc JJ |
1178 | /// assert!(expected.contains(x)); |
1179 | /// i += 1; | |
1180 | /// } | |
1181 | /// assert_eq!(i, expected.len()); | |
1182 | /// ``` | |
1183 | fn bitand(self, rhs: &HashSet<T, S>) -> HashSet<T, S> { | |
1184 | self.intersection(rhs).cloned().collect() | |
1185 | } | |
1186 | } | |
1187 | ||
85aaf69f | 1188 | #[stable(feature = "rust1", since = "1.0.0")] |
532ac7d7 | 1189 | impl<T, S> BitXor<&HashSet<T, S>> for &HashSet<T, S> |
dfeec247 XL |
1190 | where |
1191 | T: Eq + Hash + Clone, | |
1192 | S: BuildHasher + Default, | |
1a4d82fc JJ |
1193 | { |
1194 | type Output = HashSet<T, S>; | |
1195 | ||
1196 | /// Returns the symmetric difference of `self` and `rhs` as a new `HashSet<T, S>`. | |
1197 | /// | |
1198 | /// # Examples | |
1199 | /// | |
1200 | /// ``` | |
1201 | /// use std::collections::HashSet; | |
1202 | /// | |
a2a8927a XL |
1203 | /// let a = HashSet::from([1, 2, 3]); |
1204 | /// let b = HashSet::from([3, 4, 5]); | |
1a4d82fc | 1205 | /// |
85aaf69f | 1206 | /// let set = &a ^ &b; |
1a4d82fc JJ |
1207 | /// |
1208 | /// let mut i = 0; | |
1209 | /// let expected = [1, 2, 4, 5]; | |
62682a34 | 1210 | /// for x in &set { |
1a4d82fc JJ |
1211 | /// assert!(expected.contains(x)); |
1212 | /// i += 1; | |
1213 | /// } | |
1214 | /// assert_eq!(i, expected.len()); | |
1215 | /// ``` | |
1216 | fn bitxor(self, rhs: &HashSet<T, S>) -> HashSet<T, S> { | |
1217 | self.symmetric_difference(rhs).cloned().collect() | |
1218 | } | |
1219 | } | |
1220 | ||
85aaf69f | 1221 | #[stable(feature = "rust1", since = "1.0.0")] |
532ac7d7 | 1222 | impl<T, S> Sub<&HashSet<T, S>> for &HashSet<T, S> |
dfeec247 XL |
1223 | where |
1224 | T: Eq + Hash + Clone, | |
1225 | S: BuildHasher + Default, | |
1a4d82fc JJ |
1226 | { |
1227 | type Output = HashSet<T, S>; | |
1228 | ||
1229 | /// Returns the difference of `self` and `rhs` as a new `HashSet<T, S>`. | |
1230 | /// | |
1231 | /// # Examples | |
1232 | /// | |
1233 | /// ``` | |
1234 | /// use std::collections::HashSet; | |
1235 | /// | |
a2a8927a XL |
1236 | /// let a = HashSet::from([1, 2, 3]); |
1237 | /// let b = HashSet::from([3, 4, 5]); | |
1a4d82fc | 1238 | /// |
85aaf69f | 1239 | /// let set = &a - &b; |
1a4d82fc JJ |
1240 | /// |
1241 | /// let mut i = 0; | |
1242 | /// let expected = [1, 2]; | |
62682a34 | 1243 | /// for x in &set { |
1a4d82fc JJ |
1244 | /// assert!(expected.contains(x)); |
1245 | /// i += 1; | |
1246 | /// } | |
1247 | /// assert_eq!(i, expected.len()); | |
1248 | /// ``` | |
1249 | fn sub(self, rhs: &HashSet<T, S>) -> HashSet<T, S> { | |
1250 | self.difference(rhs).cloned().collect() | |
1251 | } | |
1252 | } | |
1253 | ||
cc61c64b XL |
1254 | /// An iterator over the items of a `HashSet`. |
1255 | /// | |
1256 | /// This `struct` is created by the [`iter`] method on [`HashSet`]. | |
1257 | /// See its documentation for more. | |
1258 | /// | |
3dfed10e | 1259 | /// [`iter`]: HashSet::iter |
1b1a35ee XL |
1260 | /// |
1261 | /// # Examples | |
1262 | /// | |
1263 | /// ``` | |
1264 | /// use std::collections::HashSet; | |
1265 | /// | |
a2a8927a | 1266 | /// let a = HashSet::from([1, 2, 3]); |
1b1a35ee XL |
1267 | /// |
1268 | /// let mut iter = a.iter(); | |
1269 | /// ``` | |
85aaf69f | 1270 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 1271 | pub struct Iter<'a, K: 'a> { |
1b1a35ee | 1272 | base: base::Iter<'a, K>, |
1a4d82fc JJ |
1273 | } |
1274 | ||
cc61c64b XL |
1275 | /// An owning iterator over the items of a `HashSet`. |
1276 | /// | |
dfeec247 | 1277 | /// This `struct` is created by the [`into_iter`] method on [`HashSet`] |
c295e0f8 | 1278 | /// (provided by the [`IntoIterator`] trait). See its documentation for more. |
cc61c64b | 1279 | /// |
3dfed10e | 1280 | /// [`into_iter`]: IntoIterator::into_iter |
c295e0f8 | 1281 | /// [`IntoIterator`]: crate::iter::IntoIterator |
1b1a35ee XL |
1282 | /// |
1283 | /// # Examples | |
1284 | /// | |
1285 | /// ``` | |
1286 | /// use std::collections::HashSet; | |
1287 | /// | |
a2a8927a | 1288 | /// let a = HashSet::from([1, 2, 3]); |
1b1a35ee XL |
1289 | /// |
1290 | /// let mut iter = a.into_iter(); | |
1291 | /// ``` | |
85aaf69f | 1292 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 1293 | pub struct IntoIter<K> { |
1b1a35ee | 1294 | base: base::IntoIter<K>, |
1a4d82fc JJ |
1295 | } |
1296 | ||
cc61c64b XL |
1297 | /// A draining iterator over the items of a `HashSet`. |
1298 | /// | |
1299 | /// This `struct` is created by the [`drain`] method on [`HashSet`]. | |
1300 | /// See its documentation for more. | |
1301 | /// | |
3dfed10e | 1302 | /// [`drain`]: HashSet::drain |
1b1a35ee XL |
1303 | /// |
1304 | /// # Examples | |
1305 | /// | |
1306 | /// ``` | |
1307 | /// use std::collections::HashSet; | |
1308 | /// | |
a2a8927a | 1309 | /// let mut a = HashSet::from([1, 2, 3]); |
1b1a35ee XL |
1310 | /// |
1311 | /// let mut drain = a.drain(); | |
1312 | /// ``` | |
85aaf69f | 1313 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 1314 | pub struct Drain<'a, K: 'a> { |
1b1a35ee XL |
1315 | base: base::Drain<'a, K>, |
1316 | } | |
1317 | ||
1318 | /// A draining, filtering iterator over the items of a `HashSet`. | |
1319 | /// | |
1320 | /// This `struct` is created by the [`drain_filter`] method on [`HashSet`]. | |
1321 | /// | |
1322 | /// [`drain_filter`]: HashSet::drain_filter | |
1323 | /// | |
1324 | /// # Examples | |
1325 | /// | |
1326 | /// ``` | |
1327 | /// #![feature(hash_drain_filter)] | |
1328 | /// | |
1329 | /// use std::collections::HashSet; | |
1330 | /// | |
a2a8927a | 1331 | /// let mut a = HashSet::from([1, 2, 3]); |
1b1a35ee XL |
1332 | /// |
1333 | /// let mut drain_filtered = a.drain_filter(|v| v % 2 == 0); | |
1334 | /// ``` | |
1335 | #[unstable(feature = "hash_drain_filter", issue = "59618")] | |
1336 | pub struct DrainFilter<'a, K, F> | |
1337 | where | |
1338 | F: FnMut(&K) -> bool, | |
1339 | { | |
1340 | base: base::DrainFilter<'a, K, F>, | |
1a4d82fc JJ |
1341 | } |
1342 | ||
cc61c64b XL |
1343 | /// A lazy iterator producing elements in the intersection of `HashSet`s. |
1344 | /// | |
1345 | /// This `struct` is created by the [`intersection`] method on [`HashSet`]. | |
1346 | /// See its documentation for more. | |
1347 | /// | |
3dfed10e | 1348 | /// [`intersection`]: HashSet::intersection |
1b1a35ee XL |
1349 | /// |
1350 | /// # Examples | |
1351 | /// | |
1352 | /// ``` | |
1353 | /// use std::collections::HashSet; | |
1354 | /// | |
a2a8927a XL |
1355 | /// let a = HashSet::from([1, 2, 3]); |
1356 | /// let b = HashSet::from([4, 2, 3, 4]); | |
1b1a35ee XL |
1357 | /// |
1358 | /// let mut intersection = a.intersection(&b); | |
1359 | /// ``` | |
3c0e092e XL |
1360 | #[must_use = "this returns the intersection as an iterator, \ |
1361 | without modifying either input set"] | |
85aaf69f | 1362 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1363 | pub struct Intersection<'a, T: 'a, S: 'a> { |
1364 | // iterator of the first set | |
1365 | iter: Iter<'a, T>, | |
1366 | // the second set | |
1367 | other: &'a HashSet<T, S>, | |
1368 | } | |
1369 | ||
cc61c64b XL |
1370 | /// A lazy iterator producing elements in the difference of `HashSet`s. |
1371 | /// | |
1372 | /// This `struct` is created by the [`difference`] method on [`HashSet`]. | |
1373 | /// See its documentation for more. | |
1374 | /// | |
3dfed10e | 1375 | /// [`difference`]: HashSet::difference |
1b1a35ee XL |
1376 | /// |
1377 | /// # Examples | |
1378 | /// | |
1379 | /// ``` | |
1380 | /// use std::collections::HashSet; | |
1381 | /// | |
a2a8927a XL |
1382 | /// let a = HashSet::from([1, 2, 3]); |
1383 | /// let b = HashSet::from([4, 2, 3, 4]); | |
1b1a35ee XL |
1384 | /// |
1385 | /// let mut difference = a.difference(&b); | |
1386 | /// ``` | |
3c0e092e XL |
1387 | #[must_use = "this returns the difference as an iterator, \ |
1388 | without modifying either input set"] | |
85aaf69f | 1389 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1390 | pub struct Difference<'a, T: 'a, S: 'a> { |
1391 | // iterator of the first set | |
1392 | iter: Iter<'a, T>, | |
1393 | // the second set | |
1394 | other: &'a HashSet<T, S>, | |
1395 | } | |
1396 | ||
cc61c64b XL |
1397 | /// A lazy iterator producing elements in the symmetric difference of `HashSet`s. |
1398 | /// | |
1399 | /// This `struct` is created by the [`symmetric_difference`] method on | |
1400 | /// [`HashSet`]. See its documentation for more. | |
1401 | /// | |
3dfed10e | 1402 | /// [`symmetric_difference`]: HashSet::symmetric_difference |
1b1a35ee XL |
1403 | /// |
1404 | /// # Examples | |
1405 | /// | |
1406 | /// ``` | |
1407 | /// use std::collections::HashSet; | |
1408 | /// | |
a2a8927a XL |
1409 | /// let a = HashSet::from([1, 2, 3]); |
1410 | /// let b = HashSet::from([4, 2, 3, 4]); | |
1b1a35ee XL |
1411 | /// |
1412 | /// let mut intersection = a.symmetric_difference(&b); | |
1413 | /// ``` | |
3c0e092e XL |
1414 | #[must_use = "this returns the difference as an iterator, \ |
1415 | without modifying either input set"] | |
85aaf69f | 1416 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 1417 | pub struct SymmetricDifference<'a, T: 'a, S: 'a> { |
c30ab7b3 | 1418 | iter: Chain<Difference<'a, T, S>, Difference<'a, T, S>>, |
1a4d82fc JJ |
1419 | } |
1420 | ||
cc61c64b XL |
1421 | /// A lazy iterator producing elements in the union of `HashSet`s. |
1422 | /// | |
1423 | /// This `struct` is created by the [`union`] method on [`HashSet`]. | |
1424 | /// See its documentation for more. | |
1425 | /// | |
3dfed10e | 1426 | /// [`union`]: HashSet::union |
1b1a35ee XL |
1427 | /// |
1428 | /// # Examples | |
1429 | /// | |
1430 | /// ``` | |
1431 | /// use std::collections::HashSet; | |
1432 | /// | |
a2a8927a XL |
1433 | /// let a = HashSet::from([1, 2, 3]); |
1434 | /// let b = HashSet::from([4, 2, 3, 4]); | |
1b1a35ee XL |
1435 | /// |
1436 | /// let mut union_iter = a.union(&b); | |
1437 | /// ``` | |
3c0e092e XL |
1438 | #[must_use = "this returns the union as an iterator, \ |
1439 | without modifying either input set"] | |
85aaf69f | 1440 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 1441 | pub struct Union<'a, T: 'a, S: 'a> { |
c30ab7b3 | 1442 | iter: Chain<Iter<'a, T>, Difference<'a, T, S>>, |
1a4d82fc JJ |
1443 | } |
1444 | ||
85aaf69f | 1445 | #[stable(feature = "rust1", since = "1.0.0")] |
9fa01778 | 1446 | impl<'a, T, S> IntoIterator for &'a HashSet<T, S> { |
85aaf69f SL |
1447 | type Item = &'a T; |
1448 | type IntoIter = Iter<'a, T>; | |
1449 | ||
48663c56 | 1450 | #[inline] |
5e7ed085 | 1451 | #[rustc_lint_query_instability] |
85aaf69f SL |
1452 | fn into_iter(self) -> Iter<'a, T> { |
1453 | self.iter() | |
1454 | } | |
1455 | } | |
1456 | ||
1457 | #[stable(feature = "rust1", since = "1.0.0")] | |
9fa01778 | 1458 | impl<T, S> IntoIterator for HashSet<T, S> { |
85aaf69f SL |
1459 | type Item = T; |
1460 | type IntoIter = IntoIter<T>; | |
1461 | ||
9346a6ac AL |
1462 | /// Creates a consuming iterator, that is, one that moves each value out |
1463 | /// of the set in arbitrary order. The set cannot be used after calling | |
1464 | /// this. | |
1465 | /// | |
1466 | /// # Examples | |
1467 | /// | |
1468 | /// ``` | |
1469 | /// use std::collections::HashSet; | |
1470 | /// let mut set = HashSet::new(); | |
1471 | /// set.insert("a".to_string()); | |
1472 | /// set.insert("b".to_string()); | |
1473 | /// | |
1474 | /// // Not possible to collect to a Vec<String> with a regular `.iter()`. | |
1475 | /// let v: Vec<String> = set.into_iter().collect(); | |
1476 | /// | |
1477 | /// // Will print in an arbitrary order. | |
62682a34 | 1478 | /// for x in &v { |
5e7ed085 | 1479 | /// println!("{x}"); |
9346a6ac AL |
1480 | /// } |
1481 | /// ``` | |
48663c56 | 1482 | #[inline] |
5e7ed085 | 1483 | #[rustc_lint_query_instability] |
85aaf69f | 1484 | fn into_iter(self) -> IntoIter<T> { |
1b1a35ee | 1485 | IntoIter { base: self.base.into_iter() } |
85aaf69f SL |
1486 | } |
1487 | } | |
1488 | ||
92a42be0 | 1489 | #[stable(feature = "rust1", since = "1.0.0")] |
9fa01778 | 1490 | impl<K> Clone for Iter<'_, K> { |
48663c56 | 1491 | #[inline] |
9fa01778 | 1492 | fn clone(&self) -> Self { |
1b1a35ee | 1493 | Iter { base: self.base.clone() } |
c30ab7b3 | 1494 | } |
c34b1796 | 1495 | } |
85aaf69f | 1496 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1497 | impl<'a, K> Iterator for Iter<'a, K> { |
1498 | type Item = &'a K; | |
1499 | ||
48663c56 | 1500 | #[inline] |
c30ab7b3 | 1501 | fn next(&mut self) -> Option<&'a K> { |
1b1a35ee | 1502 | self.base.next() |
c30ab7b3 | 1503 | } |
48663c56 | 1504 | #[inline] |
c30ab7b3 | 1505 | fn size_hint(&self) -> (usize, Option<usize>) { |
1b1a35ee | 1506 | self.base.size_hint() |
c30ab7b3 | 1507 | } |
85aaf69f SL |
1508 | } |
1509 | #[stable(feature = "rust1", since = "1.0.0")] | |
9fa01778 | 1510 | impl<K> ExactSizeIterator for Iter<'_, K> { |
48663c56 | 1511 | #[inline] |
c30ab7b3 | 1512 | fn len(&self) -> usize { |
1b1a35ee | 1513 | self.base.len() |
c30ab7b3 | 1514 | } |
1a4d82fc | 1515 | } |
0531ce1d | 1516 | #[stable(feature = "fused", since = "1.26.0")] |
9fa01778 | 1517 | impl<K> FusedIterator for Iter<'_, K> {} |
1a4d82fc | 1518 | |
8bb4bdeb | 1519 | #[stable(feature = "std_debug", since = "1.16.0")] |
9fa01778 | 1520 | impl<K: fmt::Debug> fmt::Debug for Iter<'_, K> { |
532ac7d7 | 1521 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
cc61c64b | 1522 | f.debug_list().entries(self.clone()).finish() |
32a655c1 SL |
1523 | } |
1524 | } | |
1525 | ||
85aaf69f | 1526 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1527 | impl<K> Iterator for IntoIter<K> { |
1528 | type Item = K; | |
1529 | ||
48663c56 | 1530 | #[inline] |
c30ab7b3 | 1531 | fn next(&mut self) -> Option<K> { |
1b1a35ee | 1532 | self.base.next() |
c30ab7b3 | 1533 | } |
48663c56 | 1534 | #[inline] |
c30ab7b3 | 1535 | fn size_hint(&self) -> (usize, Option<usize>) { |
1b1a35ee | 1536 | self.base.size_hint() |
c30ab7b3 | 1537 | } |
85aaf69f SL |
1538 | } |
1539 | #[stable(feature = "rust1", since = "1.0.0")] | |
1540 | impl<K> ExactSizeIterator for IntoIter<K> { | |
48663c56 | 1541 | #[inline] |
c30ab7b3 | 1542 | fn len(&self) -> usize { |
1b1a35ee | 1543 | self.base.len() |
c30ab7b3 | 1544 | } |
1a4d82fc | 1545 | } |
0531ce1d | 1546 | #[stable(feature = "fused", since = "1.26.0")] |
9e0c209e | 1547 | impl<K> FusedIterator for IntoIter<K> {} |
1a4d82fc | 1548 | |
8bb4bdeb | 1549 | #[stable(feature = "std_debug", since = "1.16.0")] |
32a655c1 | 1550 | impl<K: fmt::Debug> fmt::Debug for IntoIter<K> { |
532ac7d7 | 1551 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
1b1a35ee | 1552 | fmt::Debug::fmt(&self.base, f) |
32a655c1 SL |
1553 | } |
1554 | } | |
1555 | ||
85aaf69f SL |
1556 | #[stable(feature = "rust1", since = "1.0.0")] |
1557 | impl<'a, K> Iterator for Drain<'a, K> { | |
1a4d82fc JJ |
1558 | type Item = K; |
1559 | ||
48663c56 | 1560 | #[inline] |
c30ab7b3 | 1561 | fn next(&mut self) -> Option<K> { |
1b1a35ee | 1562 | self.base.next() |
c30ab7b3 | 1563 | } |
48663c56 | 1564 | #[inline] |
c30ab7b3 | 1565 | fn size_hint(&self) -> (usize, Option<usize>) { |
1b1a35ee | 1566 | self.base.size_hint() |
c30ab7b3 | 1567 | } |
85aaf69f SL |
1568 | } |
1569 | #[stable(feature = "rust1", since = "1.0.0")] | |
9fa01778 | 1570 | impl<K> ExactSizeIterator for Drain<'_, K> { |
48663c56 | 1571 | #[inline] |
c30ab7b3 | 1572 | fn len(&self) -> usize { |
1b1a35ee | 1573 | self.base.len() |
c30ab7b3 | 1574 | } |
1a4d82fc | 1575 | } |
0531ce1d | 1576 | #[stable(feature = "fused", since = "1.26.0")] |
9fa01778 | 1577 | impl<K> FusedIterator for Drain<'_, K> {} |
1a4d82fc | 1578 | |
8bb4bdeb | 1579 | #[stable(feature = "std_debug", since = "1.16.0")] |
9fa01778 | 1580 | impl<K: fmt::Debug> fmt::Debug for Drain<'_, K> { |
532ac7d7 | 1581 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
1b1a35ee XL |
1582 | fmt::Debug::fmt(&self.base, f) |
1583 | } | |
1584 | } | |
1585 | ||
1586 | #[unstable(feature = "hash_drain_filter", issue = "59618")] | |
1587 | impl<K, F> Iterator for DrainFilter<'_, K, F> | |
1588 | where | |
1589 | F: FnMut(&K) -> bool, | |
1590 | { | |
1591 | type Item = K; | |
1592 | ||
1593 | #[inline] | |
1594 | fn next(&mut self) -> Option<K> { | |
1595 | self.base.next() | |
1596 | } | |
1597 | #[inline] | |
1598 | fn size_hint(&self) -> (usize, Option<usize>) { | |
1599 | self.base.size_hint() | |
1600 | } | |
1601 | } | |
1602 | ||
1603 | #[unstable(feature = "hash_drain_filter", issue = "59618")] | |
1604 | impl<K, F> FusedIterator for DrainFilter<'_, K, F> where F: FnMut(&K) -> bool {} | |
1605 | ||
1606 | #[unstable(feature = "hash_drain_filter", issue = "59618")] | |
1607 | impl<'a, K, F> fmt::Debug for DrainFilter<'a, K, F> | |
1608 | where | |
1609 | F: FnMut(&K) -> bool, | |
1610 | { | |
1611 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | |
cdc7bbd5 | 1612 | f.debug_struct("DrainFilter").finish_non_exhaustive() |
32a655c1 SL |
1613 | } |
1614 | } | |
1615 | ||
92a42be0 | 1616 | #[stable(feature = "rust1", since = "1.0.0")] |
9fa01778 | 1617 | impl<T, S> Clone for Intersection<'_, T, S> { |
48663c56 | 1618 | #[inline] |
9fa01778 | 1619 | fn clone(&self) -> Self { |
c34b1796 AL |
1620 | Intersection { iter: self.iter.clone(), ..*self } |
1621 | } | |
1622 | } | |
1623 | ||
85aaf69f SL |
1624 | #[stable(feature = "rust1", since = "1.0.0")] |
1625 | impl<'a, T, S> Iterator for Intersection<'a, T, S> | |
dfeec247 XL |
1626 | where |
1627 | T: Eq + Hash, | |
1628 | S: BuildHasher, | |
1a4d82fc JJ |
1629 | { |
1630 | type Item = &'a T; | |
1631 | ||
48663c56 | 1632 | #[inline] |
1a4d82fc JJ |
1633 | fn next(&mut self) -> Option<&'a T> { |
1634 | loop { | |
ff7c6d11 XL |
1635 | let elt = self.iter.next()?; |
1636 | if self.other.contains(elt) { | |
1637 | return Some(elt); | |
1a4d82fc JJ |
1638 | } |
1639 | } | |
1640 | } | |
1641 | ||
48663c56 | 1642 | #[inline] |
85aaf69f | 1643 | fn size_hint(&self) -> (usize, Option<usize>) { |
1a4d82fc JJ |
1644 | let (_, upper) = self.iter.size_hint(); |
1645 | (0, upper) | |
1646 | } | |
1647 | } | |
1648 | ||
8bb4bdeb | 1649 | #[stable(feature = "std_debug", since = "1.16.0")] |
9fa01778 | 1650 | impl<T, S> fmt::Debug for Intersection<'_, T, S> |
dfeec247 XL |
1651 | where |
1652 | T: fmt::Debug + Eq + Hash, | |
1653 | S: BuildHasher, | |
32a655c1 | 1654 | { |
532ac7d7 | 1655 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
cc61c64b | 1656 | f.debug_list().entries(self.clone()).finish() |
32a655c1 SL |
1657 | } |
1658 | } | |
1659 | ||
0531ce1d | 1660 | #[stable(feature = "fused", since = "1.26.0")] |
9fa01778 | 1661 | impl<T, S> FusedIterator for Intersection<'_, T, S> |
dfeec247 XL |
1662 | where |
1663 | T: Eq + Hash, | |
1664 | S: BuildHasher, | |
c30ab7b3 SL |
1665 | { |
1666 | } | |
9e0c209e | 1667 | |
92a42be0 | 1668 | #[stable(feature = "rust1", since = "1.0.0")] |
9fa01778 | 1669 | impl<T, S> Clone for Difference<'_, T, S> { |
48663c56 | 1670 | #[inline] |
9fa01778 | 1671 | fn clone(&self) -> Self { |
c34b1796 AL |
1672 | Difference { iter: self.iter.clone(), ..*self } |
1673 | } | |
1674 | } | |
1675 | ||
85aaf69f SL |
1676 | #[stable(feature = "rust1", since = "1.0.0")] |
1677 | impl<'a, T, S> Iterator for Difference<'a, T, S> | |
dfeec247 XL |
1678 | where |
1679 | T: Eq + Hash, | |
1680 | S: BuildHasher, | |
1a4d82fc JJ |
1681 | { |
1682 | type Item = &'a T; | |
1683 | ||
48663c56 | 1684 | #[inline] |
1a4d82fc JJ |
1685 | fn next(&mut self) -> Option<&'a T> { |
1686 | loop { | |
ff7c6d11 XL |
1687 | let elt = self.iter.next()?; |
1688 | if !self.other.contains(elt) { | |
1689 | return Some(elt); | |
1a4d82fc JJ |
1690 | } |
1691 | } | |
1692 | } | |
1693 | ||
48663c56 | 1694 | #[inline] |
85aaf69f | 1695 | fn size_hint(&self) -> (usize, Option<usize>) { |
1a4d82fc JJ |
1696 | let (_, upper) = self.iter.size_hint(); |
1697 | (0, upper) | |
1698 | } | |
1699 | } | |
1700 | ||
0531ce1d | 1701 | #[stable(feature = "fused", since = "1.26.0")] |
9fa01778 | 1702 | impl<T, S> FusedIterator for Difference<'_, T, S> |
dfeec247 XL |
1703 | where |
1704 | T: Eq + Hash, | |
1705 | S: BuildHasher, | |
c30ab7b3 SL |
1706 | { |
1707 | } | |
9e0c209e | 1708 | |
8bb4bdeb | 1709 | #[stable(feature = "std_debug", since = "1.16.0")] |
9fa01778 | 1710 | impl<T, S> fmt::Debug for Difference<'_, T, S> |
dfeec247 XL |
1711 | where |
1712 | T: fmt::Debug + Eq + Hash, | |
1713 | S: BuildHasher, | |
32a655c1 | 1714 | { |
532ac7d7 | 1715 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
cc61c64b | 1716 | f.debug_list().entries(self.clone()).finish() |
32a655c1 SL |
1717 | } |
1718 | } | |
1719 | ||
92a42be0 | 1720 | #[stable(feature = "rust1", since = "1.0.0")] |
9fa01778 | 1721 | impl<T, S> Clone for SymmetricDifference<'_, T, S> { |
48663c56 | 1722 | #[inline] |
9fa01778 | 1723 | fn clone(&self) -> Self { |
c34b1796 AL |
1724 | SymmetricDifference { iter: self.iter.clone() } |
1725 | } | |
1726 | } | |
1727 | ||
85aaf69f SL |
1728 | #[stable(feature = "rust1", since = "1.0.0")] |
1729 | impl<'a, T, S> Iterator for SymmetricDifference<'a, T, S> | |
dfeec247 XL |
1730 | where |
1731 | T: Eq + Hash, | |
1732 | S: BuildHasher, | |
1a4d82fc JJ |
1733 | { |
1734 | type Item = &'a T; | |
1735 | ||
48663c56 | 1736 | #[inline] |
c30ab7b3 SL |
1737 | fn next(&mut self) -> Option<&'a T> { |
1738 | self.iter.next() | |
1739 | } | |
48663c56 | 1740 | #[inline] |
c30ab7b3 SL |
1741 | fn size_hint(&self) -> (usize, Option<usize>) { |
1742 | self.iter.size_hint() | |
1743 | } | |
1a4d82fc JJ |
1744 | } |
1745 | ||
0531ce1d | 1746 | #[stable(feature = "fused", since = "1.26.0")] |
9fa01778 | 1747 | impl<T, S> FusedIterator for SymmetricDifference<'_, T, S> |
dfeec247 XL |
1748 | where |
1749 | T: Eq + Hash, | |
1750 | S: BuildHasher, | |
c30ab7b3 SL |
1751 | { |
1752 | } | |
9e0c209e | 1753 | |
8bb4bdeb | 1754 | #[stable(feature = "std_debug", since = "1.16.0")] |
9fa01778 | 1755 | impl<T, S> fmt::Debug for SymmetricDifference<'_, T, S> |
dfeec247 XL |
1756 | where |
1757 | T: fmt::Debug + Eq + Hash, | |
1758 | S: BuildHasher, | |
32a655c1 | 1759 | { |
532ac7d7 | 1760 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
cc61c64b | 1761 | f.debug_list().entries(self.clone()).finish() |
32a655c1 SL |
1762 | } |
1763 | } | |
1764 | ||
92a42be0 | 1765 | #[stable(feature = "rust1", since = "1.0.0")] |
9fa01778 | 1766 | impl<T, S> Clone for Union<'_, T, S> { |
48663c56 | 1767 | #[inline] |
9fa01778 | 1768 | fn clone(&self) -> Self { |
c30ab7b3 SL |
1769 | Union { iter: self.iter.clone() } |
1770 | } | |
c34b1796 AL |
1771 | } |
1772 | ||
0531ce1d | 1773 | #[stable(feature = "fused", since = "1.26.0")] |
9fa01778 | 1774 | impl<T, S> FusedIterator for Union<'_, T, S> |
dfeec247 XL |
1775 | where |
1776 | T: Eq + Hash, | |
1777 | S: BuildHasher, | |
c30ab7b3 SL |
1778 | { |
1779 | } | |
9e0c209e | 1780 | |
8bb4bdeb | 1781 | #[stable(feature = "std_debug", since = "1.16.0")] |
9fa01778 | 1782 | impl<T, S> fmt::Debug for Union<'_, T, S> |
dfeec247 XL |
1783 | where |
1784 | T: fmt::Debug + Eq + Hash, | |
1785 | S: BuildHasher, | |
32a655c1 | 1786 | { |
532ac7d7 | 1787 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
cc61c64b | 1788 | f.debug_list().entries(self.clone()).finish() |
32a655c1 SL |
1789 | } |
1790 | } | |
1791 | ||
85aaf69f SL |
1792 | #[stable(feature = "rust1", since = "1.0.0")] |
1793 | impl<'a, T, S> Iterator for Union<'a, T, S> | |
dfeec247 XL |
1794 | where |
1795 | T: Eq + Hash, | |
1796 | S: BuildHasher, | |
1a4d82fc JJ |
1797 | { |
1798 | type Item = &'a T; | |
1799 | ||
48663c56 | 1800 | #[inline] |
c30ab7b3 SL |
1801 | fn next(&mut self) -> Option<&'a T> { |
1802 | self.iter.next() | |
1803 | } | |
48663c56 | 1804 | #[inline] |
c30ab7b3 SL |
1805 | fn size_hint(&self) -> (usize, Option<usize>) { |
1806 | self.iter.size_hint() | |
1807 | } | |
1a4d82fc JJ |
1808 | } |
1809 | ||
54a0048b SL |
1810 | #[allow(dead_code)] |
1811 | fn assert_covariance() { | |
c30ab7b3 SL |
1812 | fn set<'new>(v: HashSet<&'static str>) -> HashSet<&'new str> { |
1813 | v | |
1814 | } | |
1815 | fn iter<'a, 'new>(v: Iter<'a, &'static str>) -> Iter<'a, &'new str> { | |
1816 | v | |
1817 | } | |
1818 | fn into_iter<'new>(v: IntoIter<&'static str>) -> IntoIter<&'new str> { | |
1819 | v | |
1820 | } | |
dfeec247 XL |
1821 | fn difference<'a, 'new>( |
1822 | v: Difference<'a, &'static str, RandomState>, | |
1823 | ) -> Difference<'a, &'new str, RandomState> { | |
c30ab7b3 SL |
1824 | v |
1825 | } | |
dfeec247 XL |
1826 | fn symmetric_difference<'a, 'new>( |
1827 | v: SymmetricDifference<'a, &'static str, RandomState>, | |
1828 | ) -> SymmetricDifference<'a, &'new str, RandomState> { | |
c30ab7b3 SL |
1829 | v |
1830 | } | |
dfeec247 XL |
1831 | fn intersection<'a, 'new>( |
1832 | v: Intersection<'a, &'static str, RandomState>, | |
1833 | ) -> Intersection<'a, &'new str, RandomState> { | |
c30ab7b3 SL |
1834 | v |
1835 | } | |
dfeec247 XL |
1836 | fn union<'a, 'new>( |
1837 | v: Union<'a, &'static str, RandomState>, | |
1838 | ) -> Union<'a, &'new str, RandomState> { | |
c30ab7b3 SL |
1839 | v |
1840 | } | |
1841 | fn drain<'new>(d: Drain<'static, &'static str>) -> Drain<'new, &'new str> { | |
1842 | d | |
1843 | } | |
54a0048b | 1844 | } |