23 lines
782 B
Rust
23 lines
782 B
Rust
use crate::Itertools;
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/// Combine all an iterator's elements into one element by using [`Extend`].
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///
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/// [`IntoIterator`]-enabled version of [`Itertools::concat`].
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///
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/// This combinator will extend the first item with each of the rest of the
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/// items of the iterator. If the iterator is empty, the default value of
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/// `I::Item` is returned.
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///
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/// ```rust
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/// use itertools::concat;
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///
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/// let input = vec![vec![1], vec![2, 3], vec![4, 5, 6]];
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/// assert_eq!(concat(input), vec![1, 2, 3, 4, 5, 6]);
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/// ```
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pub fn concat<I>(iterable: I) -> I::Item
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where I: IntoIterator,
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I::Item: Extend<<<I as IntoIterator>::Item as IntoIterator>::Item> + IntoIterator + Default
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{
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iterable.into_iter().fold1(|mut a, b| { a.extend(b); a }).unwrap_or_else(<_>::default)
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}
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