Trait TryIndex 

pub trait TryIndex<Idx: ?Sized> {
    type Output;

    // Required methods
    fn try_index(&self, index: &Idx) -> Option<&Self::Output>;
    fn try_remove(&mut self, index: &Idx) -> Option<Self::Output>;
}

A collection that can look an element up by key without panicking when it is not there.

This is std::ops::Index with the failure made visible, plus the owning counterpart that the index operator has no equivalent of.

Required Associated Types

type Output

What is stored under a key: the value for a map, and the element itself for a set.

Required Methods

fn try_index(&self, index: &Idx) -> Option<&Self::Output>

Borrows the element stored under index, or None if there is none.

fn try_remove(&mut self, index: &Idx) -> Option<Self::Output>

Removes the element stored under index and returns it, or None if there was none.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementations on Foreign Types

impl<K, V, S> TryIndex<K> for HashMap<K, V, S>

where K: Hash + Eq, S: BuildHasher,

type Output = V

fn try_index(&self, index: &K) -> Option<&V>

fn try_remove(&mut self, index: &K) -> Option<V>

impl<K, V> TryIndex<K> for BTreeMap<K, V>

where K: Ord,

type Output = V

fn try_index(&self, index: &K) -> Option<&V>

fn try_remove(&mut self, index: &K) -> Option<V>

impl<T, S> TryIndex<T> for HashSet<T, S>

where T: Hash + Eq, S: BuildHasher,

type Output = T

fn try_index(&self, index: &T) -> Option<&T>

fn try_remove(&mut self, index: &T) -> Option<T>

impl<T> TryIndex<T> for BTreeSet<T>

where T: Ord,

type Output = T

fn try_index(&self, index: &T) -> Option<&T>

fn try_remove(&mut self, index: &T) -> Option<T>

Implementors