Trait map_ext::Update

pub trait Update<K, V> {
    fn update<F>(&mut self, key: &K, f: F)
    where
        F: FnOnce(&mut V);
}

Trait adding an update method to maps, allowing their entries to be updated.

Required Methods

fn update<F>(&mut self, key: &K, f: F) where
    F: FnOnce(&mut V), 

Update the entry for the given key by applying a function to the value.

If there is an entry in the map corresponding to key, updates the value by applying the function f to it. Otherwise, if there is no entry, does nothing.

Arguments

• key: the key to the entry to update
• f: a function taking &mut V to update the entry's value

Implementors

• impl<K, V> Update<K, V> for BTreeMap<K, V> where
    K: Ord,
    K: Copy, 
• impl<K, V> Update<K, V> for HashMap<K, V> where
    K: Hash + Eq,
    K: Copy,