[rustc.git] / vendor / itertools-0.8.2 / src / concat_impl.rs

use Itertools;

/// Combine all an iterator's elements into one element by using `Extend`.
///
/// `IntoIterator`-enabled version of `.concat()`
///
/// This combinator will extend the first item with each of the rest of the
/// items of the iterator. If the iterator is empty, the default value of
/// `I::Item` is returned.
///
/// ```rust
/// use itertools::concat;
/// 
/// let input = vec![vec![1], vec![2, 3], vec![4, 5, 6]];
/// assert_eq!(concat(input), vec![1, 2, 3, 4, 5, 6]);
/// ```
pub fn concat<I>(iterable: I) -> I::Item
    where I: IntoIterator,
          I::Item: Extend<<<I as IntoIterator>::Item as IntoIterator>::Item> + IntoIterator + Default
{
    iterable.into_iter().fold1(|mut a, b| { a.extend(b); a }).unwrap_or_else(|| <_>::default())
}
Commit	Line	Data
f20569fa XL	1	use Itertools;
	2
	3	/// Combine all an iterator's elements into one element by using `Extend`.
	4	///
	5	/// `IntoIterator`-enabled version of `.concat()`
	6	///
	7	/// This combinator will extend the first item with each of the rest of the
	8	/// items of the iterator. If the iterator is empty, the default value of
	9	/// `I::Item` is returned.
	10	///
	11	/// ```rust
	12	/// use itertools::concat;
	13	///
	14	/// let input = vec![vec![1], vec![2, 3], vec![4, 5, 6]];
	15	/// assert_eq!(concat(input), vec![1, 2, 3, 4, 5, 6]);
	16	/// ```
	17	pub fn concat<I>(iterable: I) -> I::Item
	18	where I: IntoIterator,
	19	I::Item: Extend<<<I as IntoIterator>::Item as IntoIterator>::Item> + IntoIterator + Default
	20	{
	21	iterable.into_iter().fold1(\|mut a, b\| { a.extend(b); a }).unwrap_or_else(\|\| <_>::default())
	22	}