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improve array_from_fn documenation

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Fabian Hintringer 2022-11-24 19:24:37 +01:00
parent 3f2b2eee8f
commit 480f850868
1 changed files with 13 additions and 2 deletions
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15
library/core/src/array/mod.rs
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@ -23,7 +23,8 @@
#[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 @@
/// // 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")]