# Function alloc::slice::range

``````pub fn range<R>(range: R, bounds: RangeTo<usize>) -> Range<usize>where
R: RangeBounds<usize>,``````
🔬This is a nightly-only experimental API. (`slice_range` #76393)
Expand description

Performs bounds checking of a range.

This method is similar to `Index::index` for slices, but it returns a `Range` equivalent to `range`. You can use this method to turn any range into `start` and `end` values.

`bounds` is the range of the slice to use for bounds checking. It should be a `RangeTo` range that ends at the length of the slice.

The returned `Range` is safe to pass to `slice::get_unchecked` and `slice::get_unchecked_mut` for slices with the given range.

## §Panics

Panics if `range` would be out of bounds.

## §Examples

``````#![feature(slice_range)]

use std::slice;

let v = [10, 40, 30];
assert_eq!(1..2, slice::range(1..2, ..v.len()));
assert_eq!(0..2, slice::range(..2, ..v.len()));
assert_eq!(1..3, slice::range(1.., ..v.len()));``````

Panics when `Index::index` would panic:

``````#![feature(slice_range)]

use std::slice;

let _ = slice::range(2..1, ..3);``````
``````#![feature(slice_range)]

use std::slice;

let _ = slice::range(1..4, ..3);``````
``````#![feature(slice_range)]

use std::slice;

let _ = slice::range(1..=usize::MAX, ..3);``````