[rustc.git] / vendor / itertools / src / group_map.rs

#![cfg(feature = "use_std")]

use std::collections::HashMap;
use std::hash::Hash;
use std::iter::Iterator;

/// Return a `HashMap` of keys mapped to a list of their corresponding values.
///
/// See [`.into_group_map()`](../trait.Itertools.html#method.into_group_map)
/// for more information.
pub fn into_group_map<I, K, V>(iter: I) -> HashMap<K, Vec<V>>
    where I: Iterator<Item=(K, V)>,
          K: Hash + Eq,
{
    let mut lookup = HashMap::new();

    for (key, val) in iter {
        lookup.entry(key).or_insert(Vec::new()).push(val);
    }

    lookup
}
Commit	Line	Data
532ac7d7 XL	1	#![cfg(feature = "use_std")]
	2
	3	use std::collections::HashMap;
	4	use std::hash::Hash;
	5	use std::iter::Iterator;
	6
	7	/// Return a `HashMap` of keys mapped to a list of their corresponding values.
	8	///
	9	/// See [`.into_group_map()`](../trait.Itertools.html#method.into_group_map)
	10	/// for more information.
	11	pub fn into_group_map<I, K, V>(iter: I) -> HashMap<K, Vec<V>>
	12	where I: Iterator<Item=(K, V)>,
	13	K: Hash + Eq,
	14	{
	15	let mut lookup = HashMap::new();
	16
	17	for (key, val) in iter {
	18	lookup.entry(key).or_insert(Vec::new()).push(val);
	19	}
	20
	21	lookup
	22	}