Struct serde_json::map::OccupiedEntry

pub struct OccupiedEntry<'a> { /* private fields */ }

An occupied Entry. It is part of the Entry enum.

Implementations

impl<'a> OccupiedEntry<'a>

pub fn key(&self) -> &String

Gets a reference to the key in the entry.

Examples

use serde_json::map::Entry;

let mut map = serde_json::Map::new();
map.insert("serde".to_owned(), json!(12));

match map.entry("serde") {
    Entry::Occupied(occupied) => {
        assert_eq!(occupied.key(), &"serde");
    }
    Entry::Vacant(_) => unimplemented!(),
}

pub fn get(&self) -> &Value

Gets a reference to the value in the entry.

Examples

use serde_json::map::Entry;

let mut map = serde_json::Map::new();
map.insert("serde".to_owned(), json!(12));

match map.entry("serde") {
    Entry::Occupied(occupied) => {
        assert_eq!(occupied.get(), 12);
    }
    Entry::Vacant(_) => unimplemented!(),
}

pub fn get_mut(&mut self) -> &mut Value

Gets a mutable reference to the value in the entry.

Examples

use serde_json::map::Entry;

let mut map = serde_json::Map::new();
map.insert("serde".to_owned(), json!([1, 2, 3]));

match map.entry("serde") {
    Entry::Occupied(mut occupied) => {
        occupied.get_mut().as_array_mut().unwrap().push(json!(4));
    }
    Entry::Vacant(_) => unimplemented!(),
}

assert_eq!(map["serde"].as_array().unwrap().len(), 4);

pub fn into_mut(self) -> &'a mut Value

Converts the entry into a mutable reference to its value.

Examples

use serde_json::map::Entry;

let mut map = serde_json::Map::new();
map.insert("serde".to_owned(), json!([1, 2, 3]));

match map.entry("serde") {
    Entry::Occupied(mut occupied) => {
        occupied.into_mut().as_array_mut().unwrap().push(json!(4));
    }
    Entry::Vacant(_) => unimplemented!(),
}

assert_eq!(map["serde"].as_array().unwrap().len(), 4);

pub fn insert(&mut self, value: Value) -> Value

Sets the value of the entry with the OccupiedEntry’s key, and returns the entry’s old value.

Examples

use serde_json::map::Entry;

let mut map = serde_json::Map::new();
map.insert("serde".to_owned(), json!(12));

match map.entry("serde") {
    Entry::Occupied(mut occupied) => {
        assert_eq!(occupied.insert(json!(13)), 12);
        assert_eq!(occupied.get(), 13);
    }
    Entry::Vacant(_) => unimplemented!(),
}

pub fn remove(self) -> Value

Takes the value of the entry out of the map, and returns it.

If serde_json’s “preserve_order” is enabled, .remove() is equivalent to .swap_remove(), replacing this entry’s position with the last element. If you need to preserve the relative order of the keys in the map, use .shift_remove() instead.

Examples

use serde_json::map::Entry;

let mut map = serde_json::Map::new();
map.insert("serde".to_owned(), json!(12));

match map.entry("serde") {
    Entry::Occupied(occupied) => {
        assert_eq!(occupied.remove(), 12);
    }
    Entry::Vacant(_) => unimplemented!(),
}

pub fn swap_remove(self) -> Value

Takes the value of the entry out of the map, and returns it.

Like Vec::swap_remove, the entry is removed by swapping it with the last element of the map and popping it off. This perturbs the position of what used to be the last element!

pub fn shift_remove(self) -> Value

Takes the value of the entry out of the map, and returns it.

Like Vec::remove, the entry is removed by shifting all of the elements that follow it, preserving their relative order. This perturbs the index of all of those elements!

pub fn remove_entry(self) -> (String, Value)

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

If serde_json’s “preserve_order” is enabled, .remove_entry() is equivalent to .swap_remove_entry(), replacing this entry’s position with the last element. If you need to preserve the relative order of the keys in the map, use .shift_remove_entry() instead.

Examples

use serde_json::map::Entry;

let mut map = serde_json::Map::new();
map.insert("serde".to_owned(), json!(12));

match map.entry("serde") {
    Entry::Occupied(occupied) => {
        let (key, value) = occupied.remove_entry();
        assert_eq!(key, "serde");
        assert_eq!(value, 12);
    }
    Entry::Vacant(_) => unimplemented!(),
}

pub fn swap_remove_entry(self) -> (String, Value)

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

Like Vec::swap_remove, the entry is removed by swapping it with the last element of the map and popping it off. This perturbs the position of what used to be the last element!

pub fn shift_remove_entry(self) -> (String, Value)

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

Like Vec::remove, the entry is removed by shifting all of the elements that follow it, preserving their relative order. This perturbs the index of all of those elements!