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Clarify the difference between get_mut and into_mut for OccupiedEntry

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The examples for both hash_map::OccupiedEntry::get_mut and
hash_map::OccupiedEntry::into_mut were almost identical. This led
to some confusion over the difference, namely why you would ever
use get_mut when into_mut gives alonger lifetime. Reddit thread:
https://www.reddit.com/r/rust/comments/8a5swr/why_does_hashmaps

This commit adds two lines and a comment to the example, to show
that the entry object can be re-used after calling get_mut.
This commit is contained in:
Phlosioneer
2018-04-06 15:32:54 -04:00
committed by Corey Farwell
parent 4ecf12bf0e
commit 1bc6c4b10e
1 changed files with 6 additions and 2 deletions
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8
src/libstd/collections/hash/map.rs
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@@ -2261,10 +2261,14 @@ impl<'a, K, V> OccupiedEntry<'a, K, V> {
///
/// assert_eq!(map["poneyland"], 12);
/// if let Entry::Occupied(mut o) = map.entry("poneyland") {
/// *o.get_mut() += 10;
/// *o.get_mut() += 10;
/// assert_eq!(o.get(), 22);
///
/// // We can use the same Entry multiple times.
/// *o.get_mut() += 2;
/// }
///
/// assert_eq!(map["poneyland"], 22);
/// assert_eq!(map["poneyland"], 24);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn get_mut(&mut self) -> &mut V {