Enum serde_json::map::Entry

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pub enum Entry<'a> {
    Vacant(VacantEntry<'a>),
    Occupied(OccupiedEntry<'a>),
}
Expand description

A view into a single entry in a map, which may either be vacant or occupied. This enum is constructed from the entry method on Map.

Variants§

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Vacant(VacantEntry<'a>)

A vacant Entry.

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Occupied(OccupiedEntry<'a>)

An occupied Entry.

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impl<'a> Entry<'a>

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pub fn key(&self) -> &String

Returns a reference to this entry’s key.

§Examples
let mut map = serde_json::Map::new();
assert_eq!(map.entry("serde").key(), &"serde");
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pub fn or_insert(self, default: Value) -> &'a mut Value

Ensures a value is in the entry by inserting the default if empty, and returns a mutable reference to the value in the entry.

§Examples
let mut map = serde_json::Map::new();
map.entry("serde").or_insert(json!(12));

assert_eq!(map["serde"], 12);
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pub fn or_insert_with<F>(self, default: F) -> &'a mut Value
where F: FnOnce() -> Value,

Ensures a value is in the entry by inserting the result of the default function if empty, and returns a mutable reference to the value in the entry.

§Examples
let mut map = serde_json::Map::new();
map.entry("serde").or_insert_with(|| json!("hoho"));

assert_eq!(map["serde"], "hoho".to_owned());
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pub fn and_modify<F>(self, f: F) -> Self
where F: FnOnce(&mut Value),

Provides in-place mutable access to an occupied entry before any potential inserts into the map.

§Examples
let mut map = serde_json::Map::new();
map.entry("serde")
    .and_modify(|e| *e = json!("rust"))
    .or_insert(json!("cpp"));

assert_eq!(map["serde"], "cpp");

map.entry("serde")
    .and_modify(|e| *e = json!("rust"))
    .or_insert(json!("cpp"));

assert_eq!(map["serde"], "rust");

Auto Trait Implementations§

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impl<'a> Freeze for Entry<'a>

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impl<'a> RefUnwindSafe for Entry<'a>

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impl<'a> Send for Entry<'a>

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impl<'a> Sync for Entry<'a>

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impl<'a> Unpin for Entry<'a>

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impl<'a> !UnwindSafe for Entry<'a>

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

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

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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.