Struct hashglobe::fake::HashMap

pub struct HashMap<K, V, S = RandomState>(_);

Methods

impl<K, V, S> HashMap<K, V, S> where
    K: Eq + Hash,
    S: BuildHasher, 

pub fn try_with_hasher(
    hash_builder: S
) -> Result<HashMap<K, V, S>, FailedAllocationError>

pub fn try_with_capacity_and_hasher(
    capacity: usize,
    hash_builder: S
) -> Result<HashMap<K, V, S>, FailedAllocationError>

pub fn with_capacity_and_hasher(
    capacity: usize,
    hash_builder: S
) -> HashMap<K, V, S>

pub fn try_reserve(
    &mut self,
    additional: usize
) -> Result<(), FailedAllocationError>

pub fn try_shrink_to_fit(&mut self) -> Result<(), FailedAllocationError>

pub fn try_entry(
    &mut self,
    key: K
) -> Result<Entry<K, V>, FailedAllocationError>

pub fn try_insert(
    &mut self,
    k: K,
    v: V
) -> Result<Option<V>, FailedAllocationError>

Methods from Deref<Target = StdMap<K, V, S>>

Important traits for &'a mut I

impl<'a, I> Iterator for &'a mut I where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;

pub fn hasher(&self) -> &S

Returns a reference to the map's BuildHasher.

Examples

use std::collections::HashMap;
use std::collections::hash_map::RandomState;

let hasher = RandomState::new();
let map: HashMap<isize, isize> = HashMap::with_hasher(hasher);
let hasher: &RandomState = map.hasher();

pub fn capacity(&self) -> usize

Returns the number of elements the map can hold without reallocating.

This number is a lower bound; the HashMap<K, V> might be able to hold more, but is guaranteed to be able to hold at least this many.

Examples

use std::collections::HashMap;
let map: HashMap<isize, isize> = HashMap::with_capacity(100);
assert!(map.capacity() >= 100);

pub fn reserve(&mut self, additional: usize)

Reserves capacity for at least additional more elements to be inserted in the HashMap. The collection may reserve more space to avoid frequent reallocations.

Panics

Panics if the new allocation size overflows usize.

Examples

use std::collections::HashMap;
let mut map: HashMap<&str, isize> = HashMap::new();
map.reserve(10);

pub fn shrink_to_fit(&mut self)

Shrinks the capacity of the map as much as possible. It will drop down as much as possible while maintaining the internal rules and possibly leaving some space in accordance with the resize policy.

Examples

use std::collections::HashMap;

let mut map: HashMap<isize, isize> = HashMap::with_capacity(100);
map.insert(1, 2);
map.insert(3, 4);
assert!(map.capacity() >= 100);
map.shrink_to_fit();
assert!(map.capacity() >= 2);

Important traits for Keys<'a, K, V>

impl<'a, K, V> Iterator for Keys<'a, K, V> type Item = &'a K;

pub fn keys(&self) -> Keys<K, V>

An iterator visiting all keys in arbitrary order. The iterator element type is &'a K.

Examples

use std::collections::HashMap;

let mut map = HashMap::new();
map.insert("a", 1);
map.insert("b", 2);
map.insert("c", 3);

for key in map.keys() {
    println!("{}", key);
}

Important traits for Values<'a, K, V>

impl<'a, K, V> Iterator for Values<'a, K, V> type Item = &'a V;

pub fn values(&self) -> Values<K, V>

An iterator visiting all values in arbitrary order. The iterator element type is &'a V.

Examples

use std::collections::HashMap;

let mut map = HashMap::new();
map.insert("a", 1);
map.insert("b", 2);
map.insert("c", 3);

for val in map.values() {
    println!("{}", val);
}

Important traits for ValuesMut<'a, K, V>

impl<'a, K, V> Iterator for ValuesMut<'a, K, V> type Item = &'a mut V;

pub fn values_mut(&mut self) -> ValuesMut<K, V>

An iterator visiting all values mutably in arbitrary order. The iterator element type is &'a mut V.

Examples

use std::collections::HashMap;

let mut map = HashMap::new();

map.insert("a", 1);
map.insert("b", 2);
map.insert("c", 3);

for val in map.values_mut() {
    *val = *val + 10;
}

for val in map.values() {
    println!("{}", val);
}

Important traits for Iter<'a, K, V>

impl<'a, K, V> Iterator for Iter<'a, K, V> type Item = (&'a K, &'a V);

pub fn iter(&self) -> Iter<K, V>

An iterator visiting all key-value pairs in arbitrary order. The iterator element type is (&'a K, &'a V).

Examples

use std::collections::HashMap;

let mut map = HashMap::new();
map.insert("a", 1);
map.insert("b", 2);
map.insert("c", 3);

for (key, val) in map.iter() {
    println!("key: {} val: {}", key, val);
}

Important traits for IterMut<'a, K, V>

impl<'a, K, V> Iterator for IterMut<'a, K, V> type Item = (&'a K, &'a mut V);

pub fn iter_mut(&mut self) -> IterMut<K, V>

An iterator visiting all key-value pairs in arbitrary order, with mutable references to the values. The iterator element type is (&'a K, &'a mut V).

Examples

use std::collections::HashMap;

let mut map = HashMap::new();
map.insert("a", 1);
map.insert("b", 2);
map.insert("c", 3);

// Update all values
for (_, val) in map.iter_mut() {
    *val *= 2;
}

for (key, val) in &map {
    println!("key: {} val: {}", key, val);
}

pub fn entry(&mut self, key: K) -> Entry<K, V>

Gets the given key's corresponding entry in the map for in-place manipulation.

Examples

use std::collections::HashMap;

let mut letters = HashMap::new();

for ch in "a short treatise on fungi".chars() {
    let counter = letters.entry(ch).or_insert(0);
    *counter += 1;
}

assert_eq!(letters[&'s'], 2);
assert_eq!(letters[&'t'], 3);
assert_eq!(letters[&'u'], 1);
assert_eq!(letters.get(&'y'), None);

pub fn len(&self) -> usize

Returns the number of elements in the map.

Examples

use std::collections::HashMap;

let mut a = HashMap::new();
assert_eq!(a.len(), 0);
a.insert(1, "a");
assert_eq!(a.len(), 1);

pub fn is_empty(&self) -> bool

Returns true if the map contains no elements.

Examples

use std::collections::HashMap;

let mut a = HashMap::new();
assert!(a.is_empty());
a.insert(1, "a");
assert!(!a.is_empty());

Important traits for Drain<'a, K, V>

impl<'a, K, V> Iterator for Drain<'a, K, V> type Item = (K, V);

pub fn drain(&mut self) -> Drain<K, V>

Clears the map, returning all key-value pairs as an iterator. Keeps the allocated memory for reuse.

Examples

use std::collections::HashMap;

let mut a = HashMap::new();
a.insert(1, "a");
a.insert(2, "b");

for (k, v) in a.drain().take(1) {
    assert!(k == 1 || k == 2);
    assert!(v == "a" || v == "b");
}

assert!(a.is_empty());

pub fn clear(&mut self)

Clears the map, removing all key-value pairs. Keeps the allocated memory for reuse.

Examples

use std::collections::HashMap;

let mut a = HashMap::new();
a.insert(1, "a");
a.clear();
assert!(a.is_empty());

pub fn get<Q>(&self, k: &Q) -> Option<&V> where
    K: Borrow<Q>,
    Q: Hash + Eq + ?Sized, 

Returns a reference to the value corresponding to the key.

The key may be any borrowed form of the map's key type, but Hash and Eq on the borrowed form must match those for the key type.

Examples

use std::collections::HashMap;

let mut map = HashMap::new();
map.insert(1, "a");
assert_eq!(map.get(&1), Some(&"a"));
assert_eq!(map.get(&2), None);

pub fn contains_key<Q>(&self, k: &Q) -> bool where
    K: Borrow<Q>,
    Q: Hash + Eq + ?Sized, 

Returns true if the map contains a value for the specified key.

The key may be any borrowed form of the map's key type, but Hash and Eq on the borrowed form must match those for the key type.

Examples

use std::collections::HashMap;

let mut map = HashMap::new();
map.insert(1, "a");
assert_eq!(map.contains_key(&1), true);
assert_eq!(map.contains_key(&2), false);

pub fn get_mut<Q>(&mut self, k: &Q) -> Option<&mut V> where
    K: Borrow<Q>,
    Q: Hash + Eq + ?Sized, 

Returns a mutable reference to the value corresponding to the key.

The key may be any borrowed form of the map's key type, but Hash and Eq on the borrowed form must match those for the key type.

Examples

use std::collections::HashMap;

let mut map = HashMap::new();
map.insert(1, "a");
if let Some(x) = map.get_mut(&1) {
    *x = "b";
}
assert_eq!(map[&1], "b");

pub fn insert(&mut self, k: K, v: V) -> Option<V>

Inserts a key-value pair into the map.

If the map did not have this key present, None is returned.

If the map did have this key present, the value is updated, and the old value is returned. The key is not updated, though; this matters for types that can be == without being identical. See the module-level documentation for more.

Examples

use std::collections::HashMap;

let mut map = HashMap::new();
assert_eq!(map.insert(37, "a"), None);
assert_eq!(map.is_empty(), false);

map.insert(37, "b");
assert_eq!(map.insert(37, "c"), Some("b"));
assert_eq!(map[&37], "c");

pub fn remove<Q>(&mut self, k: &Q) -> Option<V> where
    K: Borrow<Q>,
    Q: Hash + Eq + ?Sized, 

Removes a key from the map, returning the value at the key if the key was previously in the map.

The key may be any borrowed form of the map's key type, but Hash and Eq on the borrowed form must match those for the key type.

Examples

use std::collections::HashMap;

let mut map = HashMap::new();
map.insert(1, "a");
assert_eq!(map.remove(&1), Some("a"));
assert_eq!(map.remove(&1), None);

pub fn retain<F>(&mut self, f: F) where
    F: FnMut(&K, &mut V) -> bool, 

Retains only the elements specified by the predicate.

In other words, remove all pairs (k, v) such that f(&k,&mut v) returns false.

Examples

use std::collections::HashMap;

let mut map: HashMap<isize, isize> = (0..8).map(|x|(x, x*10)).collect();
map.retain(|&k, _| k % 2 == 0);
assert_eq!(map.len(), 4);

Trait Implementations

impl<K: Clone, V: Clone, S: Clone> Clone for HashMap<K, V, S>

fn clone(&self) -> HashMap<K, V, S>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

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

type Target = StdMap<K, V, S>

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

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

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.

impl<K: Hash + Eq, V, S: BuildHasher + Default> Default for HashMap<K, V, S>

fn default() -> Self

Returns the "default value" for a type.

impl<K, V, S> Debug for HashMap<K, V, S> where
    K: Eq + Hash + Debug,
    V: Debug,
    S: BuildHasher, 

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.

impl<K, V, S> PartialEq for HashMap<K, V, S> where
    K: Eq + Hash,
    V: PartialEq,
    S: BuildHasher, 

fn eq(&self, other: &HashMap<K, V, S>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

impl<K, V, S> Eq for HashMap<K, V, S> where
    K: Eq + Hash,
    V: Eq,
    S: BuildHasher, 

impl<'a, K, V, S> IntoIterator for &'a HashMap<K, V, S> where
    K: Eq + Hash,
    S: BuildHasher, 

type Item = (&'a K, &'a V)

The type of the elements being iterated over.

type IntoIter = MapIter<'a, K, V>

Which kind of iterator are we turning this into?

Important traits for Iter<'a, K, V>

impl<'a, K, V> Iterator for Iter<'a, K, V> type Item = (&'a K, &'a V);

fn into_iter(self) -> MapIter<'a, K, V>

Creates an iterator from a value.

impl<'a, K, V, S> IntoIterator for &'a mut HashMap<K, V, S> where
    K: Eq + Hash,
    S: BuildHasher, 

type Item = (&'a K, &'a mut V)

The type of the elements being iterated over.

type IntoIter = MapIterMut<'a, K, V>

Which kind of iterator are we turning this into?

Important traits for IterMut<'a, K, V>

impl<'a, K, V> Iterator for IterMut<'a, K, V> type Item = (&'a K, &'a mut V);

fn into_iter(self) -> MapIterMut<'a, K, V>

Creates an iterator from a value.