Struct serde_json::Map

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

Represents a JSON key/value type.

Methods

impl Map<String, Value>

pub fn new() -> Self

Makes a new empty Map.

pub fn with_capacity(capacity: usize) -> Self

Makes a new empty Map with the given initial capacity.

pub fn clear(&mut self)

Clears the map, removing all values.

pub fn get<Q: ?Sized>(&self, key: &Q) -> Option<&Value> where
    String: Borrow<Q>,
    Q: Ord + Eq + Hash, 

Returns a reference to the value corresponding to the key.

The key may be any borrowed form of the map's key type, but the ordering on the borrowed form must match the ordering on the key type.

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

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 the ordering on the borrowed form must match the ordering on the key type.

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

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 the ordering on the borrowed form must match the ordering on the key type.

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

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.

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

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 the ordering on the borrowed form must match the ordering on the key type.

pub fn entry<S>(&mut self, key: S) -> Entry where
    S: Into<String>, 

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

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.

Important traits for Iter<'a>

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

pub fn iter(&self) -> Iter

Gets an iterator over the entries of the map.

Important traits for IterMut<'a>

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

pub fn iter_mut(&mut self) -> IterMut

Gets a mutable iterator over the entries of the map.

Important traits for Keys<'a>

impl<'a> Iterator for Keys<'a> type Item = &'a String;

pub fn keys(&self) -> Keys

Gets an iterator over the keys of the map.

Important traits for Values<'a>

impl<'a> Iterator for Values<'a> type Item = &'a Value;

pub fn values(&self) -> Values

Gets an iterator over the values of the map.

Important traits for ValuesMut<'a>

impl<'a> Iterator for ValuesMut<'a> type Item = &'a mut Value;

pub fn values_mut(&mut self) -> ValuesMut

Gets an iterator over mutable values of the map.

Trait Implementations

impl Default for Map<String, Value>

fn default() -> Self

Returns the "default value" for a type.

impl Clone for Map<String, Value>

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Extend<(String, Value)> for Map<String, Value>

fn extend<T>(&mut self, iter: T) where
    T: IntoIterator<Item = (String, Value)>, 

Extends a collection with the contents of an iterator.

impl PartialEq<Map<String, Value>> for Map<String, Value>

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 !=.

impl<'a> IntoIterator for &'a Map<String, Value>

type Item = (&'a String, &'a Value)

The type of the elements being iterated over.

type IntoIter = Iter<'a>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<'a> IntoIterator for &'a mut Map<String, Value>

type Item = (&'a String, &'a mut Value)

The type of the elements being iterated over.

type IntoIter = IterMut<'a>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl IntoIterator for Map<String, Value>

type Item = (String, Value)

The type of the elements being iterated over.

type IntoIter = IntoIter

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl From<Map<String, Value>> for Value

fn from(f: Map<String, Value>) -> Self

Convert map (with string keys) to Value

Examples

use serde_json::{Map, Value};

let mut m = Map::new();
m.insert("Lorem".to_string(), "ipsum".into());
let x: Value = m.into();

impl<'a, Q: ?Sized> Index<&'a Q> for Map<String, Value> where
    String: Borrow<Q>,
    Q: Ord + Eq + Hash, 

Access an element of this map. Panics if the given key is not present in the map.

# use serde_json::Value;
#
# let val = &Value::String("".to_owned());
# let _ =
match *val {
    Value::String(ref s) => Some(s.as_str()),
    Value::Array(ref arr) => arr[0].as_str(),
    Value::Object(ref map) => map["type"].as_str(),
    _ => None,
}
# ;

type Output = Value

The returned type after indexing.

fn index(&self, index: &Q) -> &Value

Performs the indexing (container[index]) operation.

impl<'a, Q: ?Sized> IndexMut<&'a Q> for Map<String, Value> where
    String: Borrow<Q>,
    Q: Ord + Eq + Hash, 

Mutably access an element of this map. Panics if the given key is not present in the map.

# use serde_json::json;
#
# let mut map = serde_json::Map::new();
# map.insert("key".to_owned(), serde_json::Value::Null);
#
map["key"] = json!("value");

fn index_mut(&mut self, index: &Q) -> &mut Value

Performs the mutable indexing (container[index]) operation.

impl Debug for Map<String, Value>

fn fmt(&self, formatter: &mut Formatter) -> Result<(), Error>

Formats the value using the given formatter.

impl FromIterator<(String, Value)> for Map<String, Value>

fn from_iter<T>(iter: T) -> Self where
    T: IntoIterator<Item = (String, Value)>, 

Creates a value from an iterator.

impl Serialize for Map<String, Value>

fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error> where
    S: Serializer, 

Serialize this value into the given Serde serializer.

impl<'de> Deserialize<'de> for Map<String, Value>

fn deserialize<D>(deserializer: D) -> Result<Self, D::Error> where
    D: Deserializer<'de>, 

Deserialize this value from the given Serde deserializer.