Struct ordnung::Map

pub struct Map<K, V> { /* fields omitted */ }

A binary tree implementation of a string -> JsonValue map. You normally don't have to interact with instances of Object, much more likely you will be using the JsonValue::Object variant, which wraps around this struct.

Methods

impl<K, V> Map<K, V> where
    K: Hash + Eq, 

pub fn new() -> Self

Create a new Map.

pub fn with_capacity(capacity: usize) -> Self

Create a Map with a given capacity

pub fn insert(&mut self, key: K, value: 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.

Examples

use ordnung::Map;

let mut map = Map::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 get<Q: ?Sized>(&self, key: &Q) -> Option<&V> where
    K: Borrow<Q>,
    Q: Hash + Eq, 

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 ordnung::Map;

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

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

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 ordnung::Map;

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

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

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 ordnung::Map;

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

pub fn get_or_insert<F>(&mut self, key: K, fill: F) -> &mut V where
    F: FnOnce() -> V, 

Get a mutable reference to entry at key. Inserts a new entry by calling F if absent.

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

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 ordnung::Map;

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

pub fn len(&self) -> usize

Returns the number of elements in the map.

pub fn is_empty(&self) -> bool

Returns true if the map contains no elements.

pub fn clear(&mut self)

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

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

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

Examples

use ordnung::Map;

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

let entries: Vec<_> = map.iter().collect();

assert_eq!(
    entries,
    &[
        (&"a", &1),
        (&"b", &2),
        (&"c", &3),
    ],
);

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

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

Examples

use ordnung::Map;

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

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

// Check if values are doubled
let entries: Vec<_> = map.iter().collect();

assert_eq!(
    entries,
    &[
        (&"a", &2),
        (&"b", &4),
        (&"c", &6),
    ],
);

Trait Implementations

impl<K: Clone, V: Clone> Clone for Map<K, V>

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

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<K: Debug, V: Debug> Debug for Map<K, V>

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

Formats the value using the given formatter.

impl<'json, IK, IV, K, V> FromIterator<(IK, IV)> for Map<K, V> where
    IK: Into<K>,
    IV: Into<V>,
    K: Hash + Eq, 

fn from_iter<I>(iter: I) -> Self where
    I: IntoIterator<Item = (IK, IV)>, 

Creates a value from an iterator.

impl<'_, K, Q: ?Sized, V> Index<&'_ Q> for Map<K, V> where
    K: Eq + Hash + Borrow<Q>,
    Q: Eq + Hash, 

type Output = V

The returned type after indexing.

fn index(&self, key: &Q) -> &V

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

Panics

Panics if the key is not present in the HashMap.

impl<K, V> PartialEq<Map<K, V>> for Map<K, V> where
    K: Hash + Eq,
    V: PartialEq, 

fn eq(&self, other: &Self) -> bool

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

#[must_use]fn ne(&self, other: &Rhs) -> bool

This method tests for !=.