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| -rw-r--r-- | src/libcollections/btree/map.rs | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/src/libcollections/btree/map.rs b/src/libcollections/btree/map.rs index 01096c1fd4e..5fb963b15ce 100644 --- a/src/libcollections/btree/map.rs +++ b/src/libcollections/btree/map.rs @@ -1288,6 +1288,30 @@ impl<K, V> BTreeMap<K, V> { impl<K: Ord, V> BTreeMap<K, V> { /// Gets the given key's corresponding entry in the map for in-place manipulation. + /// + /// # Examples + /// + /// ``` + /// use std::collections::BTreeMap; + /// use std::collections::btree_map::Entry; + /// + /// let mut count: BTreeMap<&str, uint> = BTreeMap::new(); + /// + /// // count the number of occurrences of letters in the vec + /// for x in vec!["a","b","a","c","a","b"].iter() { + /// match count.entry(*x) { + /// Entry::Vacant(view) => { + /// view.set(1); + /// }, + /// Entry::Occupied(mut view) => { + /// let v = view.get_mut(); + /// *v += 1; + /// }, + /// } + /// } + /// + /// assert_eq!(count["a"], 3u); + /// ``` pub fn entry<'a>(&'a mut self, mut key: K) -> Entry<'a, K, V> { // same basic logic of `swap` and `pop`, blended together let mut stack = stack::PartialSearchStack::new(self); |