diff options
Diffstat (limited to 'library/alloc/src')
| -rw-r--r-- | library/alloc/src/lib.rs | 1 | ||||
| -rw-r--r-- | library/alloc/src/vec/mod.rs | 25 |
2 files changed, 26 insertions, 0 deletions
diff --git a/library/alloc/src/lib.rs b/library/alloc/src/lib.rs index ebc30c08910..20b7d0afa87 100644 --- a/library/alloc/src/lib.rs +++ b/library/alloc/src/lib.rs @@ -170,6 +170,7 @@ #![feature(unicode_internals)] #![feature(unsize)] #![feature(utf8_chunks)] +#![feature(vec_pop_if)] // tidy-alphabetical-end // // Language features: diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs index 3062f8664b7..8ca8046dac5 100644 --- a/library/alloc/src/vec/mod.rs +++ b/library/alloc/src/vec/mod.rs @@ -2058,6 +2058,31 @@ impl<T, A: Allocator> Vec<T, A> { } } + /// Removes and returns the last element in a vector if the predicate + /// returns `true`, or [`None`] if the predicate returns false or the vector + /// is empty. + /// + /// # Examples + /// + /// ``` + /// #![feature(vec_pop_if)] + /// + /// let mut vec = vec![1, 2, 3, 4]; + /// let pred = |x: &mut i32| *x % 2 == 0; + /// + /// assert_eq!(vec.pop_if(pred), Some(4)); + /// assert_eq!(vec, [1, 2, 3]); + /// assert_eq!(vec.pop_if(pred), None); + /// ``` + #[unstable(feature = "vec_pop_if", issue = "122741")] + pub fn pop_if<F>(&mut self, f: F) -> Option<T> + where + F: FnOnce(&mut T) -> bool, + { + let last = self.last_mut()?; + if f(last) { self.pop() } else { None } + } + /// Moves all the elements of `other` into `self`, leaving `other` empty. /// /// # Panics |
