pub struct Map<K, V> { /* private fields */ }
Expand description

Represents a JSON key/value type.

Implementations

Makes a new empty Map.

Makes a new empty Map with the given initial capacity.

Clears the map, removing all values.

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.

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.

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.

Returns the key-value pair matching the given 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.

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.

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.

source

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

Removes a key from the map, returning the stored key and value 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.

Moves all elements from other into self, leaving other empty.

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

Returns the number of elements in the map.

Returns true if the map contains no elements.

Gets an iterator over the entries of the map.

Gets a mutable iterator over the entries of the map.

Gets an iterator over the keys of the map.

Gets an iterator over the values of the map.

Gets an iterator over mutable values of the map.

Retains only the elements specified by the predicate.

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

Trait Implementations

Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

Formats the value using the given formatter. Read more

Returns the “default value” for a type. Read more

Deserialize this value from the given Serde deserializer. Read more

Extends a collection with the contents of an iterator. Read more

🔬 This is a nightly-only experimental API. (extend_one)

Extends a collection with exactly one element.

🔬 This is a nightly-only experimental API. (extend_one)

Reserves capacity in a collection for the given number of additional elements. Read more

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();

Creates a value from an iterator. Read more

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

match val {
    Value::String(s) => Some(s.as_str()),
    Value::Array(arr) => arr[0].as_str(),
    Value::Object(map) => map["type"].as_str(),
    _ => None,
}

The returned type after indexing.

Performs the indexing (container[index]) operation. Read more

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

map["key"] = json!("value");

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

The type of the elements being iterated over.

Which kind of iterator are we turning this into?

Creates an iterator from a value. Read more

The type of the elements being iterated over.

Which kind of iterator are we turning this into?

Creates an iterator from a value. Read more

The type of the elements being iterated over.

Which kind of iterator are we turning this into?

Creates an iterator from a value. Read more

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

This method tests for !=.

Serialize this value into the given Serde serializer. Read more

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The resulting type after obtaining ownership.

Creates owned data from borrowed data, usually by cloning. Read more

Uses borrowed data to replace owned data, usually by cloning. Read more

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.