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Commit addb1c8

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add Iterator::contains
1 parent 59aa1e8 commit addb1c8

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5 files changed

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‎library/core/src/iter/traits/iterator.rs

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@@ -2826,6 +2826,43 @@ pub trait Iterator {
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self.try_fold((), check(f)) == ControlFlow::Break(())
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}
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/// Tests whether a value is contained in the iterator.
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///
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/// `contains()` is short-circuiting; in other words, it will stop processing
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/// as soon as the function finds the item in the `Iterator`.
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///
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/// This method checks the whole iterator, which is O(n). If the iterator is a sorted
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/// slice, [`binary_search`](slice::binary_search) may be faster. If this is an iterator
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/// on collections that have a `.contains()` or `.contains_key()` method (such as
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/// `HashMap` or `BtreeSet`), using those methods directly will be faster.
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///
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/// # Examples
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///
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/// Basic usage:
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///
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/// ```
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/// #![feature(iter_contains)]
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/// assert!([1, 2, 3].iter().contains(2));
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/// assert!(![1, 2, 3].iter().contains(5));
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/// ```
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///
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/// [`Iterator::contains`] can be used where [`slice::contains`] cannot be used:
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///
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/// ```
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/// #![feature(iter_contains)]
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/// let s = [String::from("a"), String::from("b"), String::from("c")];
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/// assert!(s.iter().contains("b"));
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/// ```
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#[inline]
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#[unstable(feature = "iter_contains", issue = "127494")]
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fn contains<Q>(&mut self, item: Q) -> bool
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where
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Q: PartialEq<Self::Item> + ?Sized,
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Self: Sized,
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{
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self.any(|elem| item == elem)
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}
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/// Searches for an element of an iterator that satisfies a predicate.
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///
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/// `find()` takes a closure that returns `true` or `false`. It applies

‎library/core/src/lib.rs

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@@ -110,6 +110,7 @@
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#![feature(internal_impls_macro)]
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#![feature(ip)]
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#![feature(is_ascii_octdigit)]
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#![feature(iter_contains)]
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#![feature(lazy_get)]
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#![feature(link_cfg)]
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#![feature(offset_of_enum)]

‎library/core/src/str/iter.rs

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@@ -331,6 +331,14 @@ impl Iterator for Bytes<'_> {
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self.0.any(f)
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}
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#[inline]
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fn contains<Q>(&mut self, item: Q) -> bool
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where
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Q: PartialEq<Self::Item> + ?Sized,
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{
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self.0.contains(item)
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}
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#[inline]
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fn find<P>(&mut self, predicate: P) -> Option<Self::Item>
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where

‎library/coretests/tests/iter/traits/iterator.rs

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@@ -272,6 +272,17 @@ fn test_any() {
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assert!(!v[..0].iter().any(|_| panic!()));
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}
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#[test]
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fn test_iterator_contains() {
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let v: Box<[isize]> = Box::new([1, 2, 3, 4, 5]);
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assert_eq!(true, v.iter().contains(&3));
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assert_eq!(v.iter().contains(&3), v.iter().any(|&x| x == 3));
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assert_eq!(false, v.iter().contains(&10));
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assert_eq!(v.iter().contains(&10), v.iter().any(|&x| x == 10));
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assert_eq!(true, Iterator::contains(&mut (1isize..=5), 3));
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assert_eq!(false, Iterator::contains(&mut (1isize..=5), 10));
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}
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#[test]
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fn test_find() {
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let v: &[isize] = &[1, 3, 9, 27, 103, 14, 11];

‎library/coretests/tests/lib.rs

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@@ -55,6 +55,7 @@
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#![feature(iter_array_chunks)]
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#![feature(iter_chain)]
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#![feature(iter_collect_into)]
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#![feature(iter_contains)]
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#![feature(iter_intersperse)]
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#![feature(iter_is_partitioned)]
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#![feature(iter_map_windows)]

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