EnumEntry

1.0.0 ·Source

pub enum Entry<'a, 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.

Thisenum is constructed from theentry method onHashMap.

Variants§

§1.0.0

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

An occupied entry.

§1.0.0

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

A vacant entry.

Implementations§

Source §

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

1.0.0 ·Source

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

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

§Examples

usestd::collections::HashMap;letmutmap: 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 fnor_insert_with<F:FnOnce() -> V>(self, default: F) ->&'a mut 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

usestd::collections::HashMap;letmutmap = HashMap::new();letvalue ="hoho";map.entry("poneyland").or_insert_with(|| value);assert_eq!(map["poneyland"],"hoho");

1.50.0 ·Source

pub fnor_insert_with_key<F:FnOnce(&K) -> V>(self, default: F) ->&'a mut 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 defaultfunction 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 isunnecessary, unlike with.or_insert_with(|| ... ).

§Examples

usestd::collections::HashMap;letmutmap: 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 fnkey(&self) ->&K

Returns a reference to this entry’s key.

§Examples

usestd::collections::HashMap;letmutmap: HashMap<&str, u32> = HashMap::new();assert_eq!(map.entry("poneyland").key(),&"poneyland");

1.26.0 ·Source

pub fnand_modify<F>(self, f: F) -> Self
where F:FnOnce(&mut V),

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

§Examples

usestd::collections::HashMap;letmutmap: 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);

1.83.0 ·Source

pub fninsert_entry(self, value: V) ->OccupiedEntry<'a, K, V>

Sets the value of the entry, and returns anOccupiedEntry.

§Examples

usestd::collections::HashMap;letmutmap: HashMap<&str, String> = HashMap::new();letentry = map.entry("poneyland").insert_entry("hoho".to_string());assert_eq!(entry.key(),&"poneyland");

Source §

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

1.28.0 ·Source

pub fnor_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

usestd::collections::HashMap;letmutmap: HashMap<&str,Option<u32>> = HashMap::new();map.entry("poneyland").or_default();assert_eq!(map["poneyland"],None);