documentation update to demonstrate mutability

This commit is contained in:
toidiu 2017-09-09 16:56:12 -04:00
parent 088216fb99
commit c430fa8084

View File

@ -362,16 +362,25 @@ impl str {
/// # Examples
///
/// ```
/// let mut v = String::from("🗻∈🌏");
///
/// assert_eq!(Some("🗻"), v.get_mut(0..4).map(|v| &*v));
///
/// // indices not on UTF-8 sequence boundaries
/// assert!(v.get_mut(1..).is_none());
/// assert!(v.get_mut(..8).is_none());
/// use std::ascii::AsciiExt;
///
/// let mut v = String::from("hello");
/// // correct length
/// assert!(v.get_mut(0..5).is_some());
/// // out of bounds
/// assert!(v.get_mut(..42).is_none());
/// assert_eq!(Some("he"), v.get_mut(0..2).map(|v| &*v));
///
/// assert_eq!("hello", v);
/// {
/// let s = v.get_mut(0..2);
/// let s = s.map(|s| {
/// s.make_ascii_uppercase();
/// &*s
/// });
/// assert_eq!(Some("HE"), s);
/// }
/// assert_eq!("HEllo", v);
/// ```
#[stable(feature = "str_checked_slicing", since = "1.20.0")]
#[inline]