Enum parry3d::utils::hashmap::Entry

1.0.0 · source ·
pub enum Entry<'a, K, V>
where K: 'a, V: 'a,
{ Occupied(OccupiedEntry<'a, K, V>), Vacant(VacantEntry<'a, K, V>), }
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 HashMap.

Variants§

§1.0.0

Occupied(OccupiedEntry<'a, K, V>)

An occupied entry.

§1.0.0

Vacant(VacantEntry<'a, K, V>)

A vacant entry.

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impl<'a, K, V> Entry<'a, K, V>

1.0.0 · source

pub fn or_insert(self, default: V) -> &'a mut V

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
use std::collections::HashMap;

let mut map: HashMap<&str, u32> = HashMap::new();

map.entry("poneyland").or_insert(3);
assert_eq!(map["poneyland"], 3);

*map.entry("poneyland").or_insert(10) *= 2;
assert_eq!(map["poneyland"], 6);
1.0.0 · source

pub fn or_insert_with<F>(self, default: F) -> &'a mut V
where F: FnOnce() -> V,

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
use std::collections::HashMap;

let mut map = HashMap::new();
let value = "hoho";

map.entry("poneyland").or_insert_with(|| value);

assert_eq!(map["poneyland"], "hoho");
1.50.0 · source

pub fn or_insert_with_key<F>(self, default: F) -> &'a mut V
where F: FnOnce(&K) -> V,

Ensures a value is in the entry by inserting, if empty, the result of the default function. This method allows for generating key-derived values for insertion by providing the default function a reference to the key that was moved during the .entry(key) method call.

The reference to the moved key is provided so that cloning or copying the key is unnecessary, unlike with .or_insert_with(|| ... ).

§Examples
use std::collections::HashMap;

let mut map: HashMap<&str, usize> = HashMap::new();

map.entry("poneyland").or_insert_with_key(|key| key.chars().count());

assert_eq!(map["poneyland"], 9);
1.10.0 · source

pub fn key(&self) -> &K

Returns a reference to this entry’s key.

§Examples
use std::collections::HashMap;

let mut map: HashMap<&str, u32> = HashMap::new();
assert_eq!(map.entry("poneyland").key(), &"poneyland");
1.26.0 · source

pub fn and_modify<F>(self, f: F) -> Entry<'a, K, V>
where F: FnOnce(&mut V),

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

§Examples
use std::collections::HashMap;

let mut map: HashMap<&str, u32> = HashMap::new();

map.entry("poneyland")
   .and_modify(|e| { *e += 1 })
   .or_insert(42);
assert_eq!(map["poneyland"], 42);

map.entry("poneyland")
   .and_modify(|e| { *e += 1 })
   .or_insert(42);
assert_eq!(map["poneyland"], 43);
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pub fn insert_entry(self, value: V) -> OccupiedEntry<'a, K, V>

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

Sets the value of the entry, and returns an OccupiedEntry.

§Examples
#![feature(entry_insert)]
use std::collections::HashMap;

let mut map: HashMap<&str, String> = HashMap::new();
let entry = map.entry("poneyland").insert_entry("hoho".to_string());

assert_eq!(entry.key(), &"poneyland");
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impl<'a, K, V> Entry<'a, K, V>
where V: Default,

1.28.0 · source

pub fn or_default(self) -> &'a mut V

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

§Examples
use std::collections::HashMap;

let mut map: HashMap<&str, Option<u32>> = HashMap::new();
map.entry("poneyland").or_default();

assert_eq!(map["poneyland"], None);

Trait Implementations§

1.12.0 · source§

impl<K, V> Debug for Entry<'_, K, V>
where K: Debug, V: Debug,

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fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter. Read more

Auto Trait Implementations§

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impl<'a, K, V> Freeze for Entry<'a, K, V>
where K: Freeze,

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impl<'a, K, V> RefUnwindSafe for Entry<'a, K, V>

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impl<'a, K, V> Send for Entry<'a, K, V>
where K: Send, V: Send,

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impl<'a, K, V> Sync for Entry<'a, K, V>
where K: Sync, V: Sync,

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impl<'a, K, V> Unpin for Entry<'a, K, V>
where K: Unpin,

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impl<'a, K, V> !UnwindSafe for Entry<'a, K, V>

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> Downcast for T
where T: Any,

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fn into_any(self: Box<T>) -> Box<dyn Any>

Convert Box<dyn Trait> (where Trait: Downcast) to Box<dyn Any>. Box<dyn Any> can then be further downcast into Box<ConcreteType> where ConcreteType implements Trait.
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fn into_any_rc(self: Rc<T>) -> Rc<dyn Any>

Convert Rc<Trait> (where Trait: Downcast) to Rc<Any>. Rc<Any> can then be further downcast into Rc<ConcreteType> where ConcreteType implements Trait.
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fn as_any(&self) -> &(dyn Any + 'static)

Convert &Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &Any’s vtable from &Trait’s.
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fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)

Convert &mut Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &mut Any’s vtable from &mut Trait’s.
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impl<T> DowncastSync for T
where T: Any + Send + Sync,

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fn into_any_arc(self: Arc<T>) -> Arc<dyn Any + Sync + Send>

Convert Arc<Trait> (where Trait: Downcast) to Arc<Any>. Arc<Any> can then be further downcast into Arc<ConcreteType> where ConcreteType implements Trait.
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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> IntoEither for T

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fn into_either(self, into_left: bool) -> Either<Self, Self>

Converts self into a Left variant of Either<Self, Self> if into_left is true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

Converts self into a Left variant of Either<Self, Self> if into_left(&self) returns true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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impl<T> Same for T

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type Output = T

Should always be Self
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impl<SS, SP> SupersetOf<SS> for SP
where SS: SubsetOf<SP>,

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fn to_subset(&self) -> Option<SS>

The inverse inclusion map: attempts to construct self from the equivalent element of its superset. Read more
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fn is_in_subset(&self) -> bool

Checks if self is actually part of its subset T (and can be converted to it).
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fn to_subset_unchecked(&self) -> SS

Use with care! Same as self.to_subset but without any property checks. Always succeeds.
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fn from_subset(element: &SS) -> SP

The inclusion map: converts self to the equivalent element of its superset.
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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.