pub struct LinkedHashMap<K, V, S = RandomState> { /* private fields */ }
Expand description

A version of HashMap that has a user controllable order for its entries.

It achieves this by keeping its entries in an internal linked list and using a HashMap to point at nodes in this linked list.

The order of entries defaults to “insertion order”, but the user can also modify the order of existing entries by manually moving them to the front or back.

There are two kinds of methods that modify the order of the internal list:

  • Methods that have names like to_front and to_back will unsurprisingly move an existing entry to the front or back
  • Methods that have the word insert will insert a new entry ot the back of the list, and if that method might replace an entry, that method will also move that existing entry to the back.

Implementations§

Inserts the given key / value pair at the back of the internal linked list.

Returns the previously set value, if one existed prior to this call. After this call, calling LinkedHashMap::back will return a reference to this key / value pair.

If the given key is not in this map, inserts the key / value pair at the back of the internal linked list and returns None, otherwise, replaces the existing value with the given value without moving the entry in the internal linked list and returns the previous value.

source

pub fn remove_entry<Q>(&mut self, k: &Q) -> Option<(K, V)>where
    K: Borrow<Q>,
    Q: Hash + Eq + ?Sized,

If an entry with this key exists, move it to the front of the list and return a reference to the value.

If an entry with this key exists, move it to the back of the list and return a reference to the value.

source

pub fn raw_entry(&self) -> RawEntryBuilder<'_, K, V, S>

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pub fn raw_entry_mut(&mut self) -> RawEntryBuilderMut<'_, K, V, S>

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
Executes the destructor for this type. 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
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
Creates a value from an iterator. Read more
Feeds this value into the given Hasher. Read more
Feeds a slice of this type into the given Hasher. Read more
The returned type after indexing.
Performs the indexing (container[index]) operation. Read more
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 returns an Ordering between self and other. Read more
Compares and returns the maximum of two values. Read more
Compares and returns the minimum of two values. Read more
Restrict a value to a certain interval. Read more
This method tests for self and other values to be equal, and is used by ==. Read more
This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason. Read more
This method returns an ordering between self and other values if one exists. Read more
This method tests less than (for self and other) and is used by the < operator. Read more
This method tests less than or equal to (for self and other) and is used by the <= operator. Read more
This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
This method tests greater than (for self and other) and is used by the > operator. 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
Compare self to key and return true if they are equal.

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.