diff options
| -rw-r--r-- | library/core/src/iter/traits/iterator.rs | 21 |
1 files changed, 16 insertions, 5 deletions
diff --git a/library/core/src/iter/traits/iterator.rs b/library/core/src/iter/traits/iterator.rs index 7a3700d6923..648895e12f1 100644 --- a/library/core/src/iter/traits/iterator.rs +++ b/library/core/src/iter/traits/iterator.rs @@ -2028,7 +2028,8 @@ pub trait Iterator { self.try_fold((), call(f)) } - /// An iterator method that applies a function, producing a single, final value. + /// Folds every element into an accumulator by applying an operation, + /// returning the final result. /// /// `fold()` takes two arguments: an initial value, and a closure with two /// arguments: an 'accumulator', and an element. The closure returns the value that @@ -2049,6 +2050,9 @@ pub trait Iterator { /// may not terminate for infinite iterators, even on traits for which a /// result is determinable in finite time. /// + /// Note: [`reduce()`] can be used to use the first element as the initial + /// value, if the accumulator type and item type is the same. + /// /// # Note to Implementors /// /// Several of the other (forward) methods have default implementations in @@ -2104,6 +2108,8 @@ pub trait Iterator { /// // they're the same /// assert_eq!(result, result2); /// ``` + /// + /// [`reduce()`]: Iterator::reduce #[doc(alias = "reduce")] #[doc(alias = "inject")] #[inline] @@ -2120,10 +2126,15 @@ pub trait Iterator { accum } - /// The same as [`fold()`], but uses the first element in the - /// iterator as the initial value, folding every subsequent element into it. - /// If the iterator is empty, return [`None`]; otherwise, return the result - /// of the fold. + /// Reduces the elements to a single one, by repeatedly applying a reducing + /// operation. + /// + /// If the iterator is empty, returns [`None`]; otherwise, returns the + /// result of the reduction. + /// + /// For iterators with at least one element, this is the same as [`fold()`] + /// with the first element of the iterator as the initial value, folding + /// every subsequent element into it. /// /// [`fold()`]: Iterator::fold /// |