Jakub Kotur | a425e55 | 2020-12-21 17:28:15 +0100 | [diff] [blame^] | 1 | use crate::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 | } |