From 480f850868e581cf51dab1ab8bce67f371c4db64 Mon Sep 17 00:00:00 2001 From: Fabian Hintringer Date: Thu, 24 Nov 2022 19:24:37 +0100 Subject: [PATCH] improve array_from_fn documenation --- library/core/src/array/mod.rs | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/library/core/src/array/mod.rs b/library/core/src/array/mod.rs index 2090756d7a3..773fd0b4a18 100644 --- a/library/core/src/array/mod.rs +++ b/library/core/src/array/mod.rs @@ -23,7 +23,8 @@ mod iter; #[stable(feature = "array_value_iter", since = "1.51.0")] pub use iter::IntoIter; -/// Creates an array `[T; N]` where each array element `T` is returned by the `cb` call. +/// Creates an array of type [T; N], where each element `T` is the returned value from `cb` +/// using that element's index. /// /// # Arguments /// @@ -36,8 +37,18 @@ pub use iter::IntoIter; /// // elements to produce is the length of array down there: only arrays of /// // equal lengths can be compared, so the const generic parameter `N` is /// // inferred to be 5, thus creating array of 5 elements. -/// let array = core::array::from_fn(|i| i); +/// +/// let array: [_; 5] = core::array::from_fn(|i| i); +/// // indexes are: 0 1 2 3 4 /// assert_eq!(array, [0, 1, 2, 3, 4]); +/// +/// let array2: [_; 8] = core::array::from_fn(|i| i * 2); +/// // indexes are: 0 1 2 3 4 5 6 7 +/// assert_eq!(array2, [0, 2, 4, 6, 8, 10, 12, 14]); +/// +/// let bool_arr: [bool; 5] = core::array::from_fn(|i| i % 2 == 0); +/// // indexes are: 0 1 2 3 4 +/// assert_eq!(bool_arr, [true, false, true, false, true]); /// ``` #[inline] #[stable(feature = "array_from_fn", since = "1.63.0")]