1.0.0[−][src]Struct std::collections::hash_map::HashMap
A hash map implemented with quadratic probing and SIMD lookup.
By default, HashMap
uses a hashing algorithm selected to provide
resistance against HashDoS attacks. The algorithm is randomly seeded, and a
reasonable best-effort is made to generate this seed from a high quality,
secure source of randomness provided by the host without blocking the
program. Because of this, the randomness of the seed depends on the output
quality of the system's random number generator when the seed is created.
In particular, seeds generated when the system's entropy pool is abnormally
low such as during system boot may be of a lower quality.
The default hashing algorithm is currently SipHash 1-3, though this is subject to change at any point in the future. While its performance is very competitive for medium sized keys, other hashing algorithms will outperform it for small keys such as integers as well as large keys such as long strings, though those algorithms will typically not protect against attacks such as HashDoS.
The hashing algorithm can be replaced on a per-HashMap
basis using the
default
, with_hasher
, and with_capacity_and_hasher
methods. Many
alternative algorithms are available on crates.io, such as the fnv
crate.
It is required that the keys implement the Eq
and Hash
traits, although
this can frequently be achieved by using #[derive(PartialEq, Eq, Hash)]
.
If you implement these yourself, it is important that the following
property holds:
k1 == k2 -> hash(k1) == hash(k2)
In other words, if two keys are equal, their hashes must be equal.
It is a logic error for a key to be modified in such a way that the key's
hash, as determined by the Hash
trait, or its equality, as determined by
the Eq
trait, changes while it is in the map. This is normally only
possible through Cell
, RefCell
, global state, I/O, or unsafe code.
The hash table implementation is a Rust port of Google's SwissTable. The original C++ version of SwissTable can be found here, and this CppCon talk gives an overview of how the algorithm works.
Examples
use std::collections::HashMap; // Type inference lets us omit an explicit type signature (which // would be `HashMap<String, String>` in this example). let mut book_reviews = HashMap::new(); // Review some books. book_reviews.insert( "Adventures of Huckleberry Finn".to_string(), "My favorite book.".to_string(), ); book_reviews.insert( "Grimms' Fairy Tales".to_string(), "Masterpiece.".to_string(), ); book_reviews.insert( "Pride and Prejudice".to_string(), "Very enjoyable.".to_string(), ); book_reviews.insert( "The Adventures of Sherlock Holmes".to_string(), "Eye lyked it alot.".to_string(), ); // Check for a specific one. // When collections store owned values (String), they can still be // queried using references (&str). if !book_reviews.contains_key("Les Misérables") { println!("We've got {} reviews, but Les Misérables ain't one.", book_reviews.len()); } // oops, this review has a lot of spelling mistakes, let's delete it. book_reviews.remove("The Adventures of Sherlock Holmes"); // Look up the values associated with some keys. let to_find = ["Pride and Prejudice", "Alice's Adventure in Wonderland"]; for &book in &to_find { match book_reviews.get(book) { Some(review) => println!("{}: {}", book, review), None => println!("{} is unreviewed.", book) } } // Look up the value for a key (will panic if the key is not found). println!("Review for Jane: {}", book_reviews["Pride and Prejudice"]); // Iterate over everything. for (book, review) in &book_reviews { println!("{}: \"{}\"", book, review); }Run
HashMap
also implements an Entry API
, which allows
for more complex methods of getting, setting, updating and removing keys and
their values:
use std::collections::HashMap; // type inference lets us omit an explicit type signature (which // would be `HashMap<&str, u8>` in this example). let mut player_stats = HashMap::new(); fn random_stat_buff() -> u8 { // could actually return some random value here - let's just return // some fixed value for now 42 } // insert a key only if it doesn't already exist player_stats.entry("health").or_insert(100); // insert a key using a function that provides a new value only if it // doesn't already exist player_stats.entry("defence").or_insert_with(random_stat_buff); // update a key, guarding against the key possibly not being set let stat = player_stats.entry("attack").or_insert(100); *stat += random_stat_buff();Run
The easiest way to use HashMap
with a custom key type is to derive Eq
and Hash
.
We must also derive PartialEq
.
use std::collections::HashMap; #[derive(Hash, Eq, PartialEq, Debug)] struct Viking { name: String, country: String, } impl Viking { /// Creates a new Viking. fn new(name: &str, country: &str) -> Viking { Viking { name: name.to_string(), country: country.to_string() } } } // Use a HashMap to store the vikings' health points. let mut vikings = HashMap::new(); vikings.insert(Viking::new("Einar", "Norway"), 25); vikings.insert(Viking::new("Olaf", "Denmark"), 24); vikings.insert(Viking::new("Harald", "Iceland"), 12); // Use derived implementation to print the status of the vikings. for (viking, health) in &vikings { println!("{:?} has {} hp", viking, health); }Run
A HashMap
with fixed list of elements can be initialized from an array:
use std::collections::HashMap; fn main() { let timber_resources: HashMap<&str, i32> = [("Norway", 100), ("Denmark", 50), ("Iceland", 10)] .iter().cloned().collect(); // use the values stored in map }Run
Methods
impl<K: Hash + Eq, V> HashMap<K, V, RandomState>
[src]
pub fn new() -> HashMap<K, V, RandomState>
[src]
Creates an empty HashMap
.
The hash map is initially created with a capacity of 0, so it will not allocate until it is first inserted into.
Examples
use std::collections::HashMap; let mut map: HashMap<&str, i32> = HashMap::new();Run
pub fn with_capacity(capacity: usize) -> HashMap<K, V, RandomState>
[src]
impl<K, V, S> HashMap<K, V, S>
[src]
pub fn capacity(&self) -> usize
[src]
Returns the number of elements the map can hold without reallocating.
This number is a lower bound; the HashMap<K, V>
might be able to hold
more, but is guaranteed to be able to hold at least this many.
Examples
use std::collections::HashMap; let map: HashMap<i32, i32> = HashMap::with_capacity(100); assert!(map.capacity() >= 100);Run
ⓘImportant traits for Keys<'a, K, V>pub fn keys(&self) -> Keys<K, V>
[src]
An iterator visiting all keys in arbitrary order.
The iterator element type is &'a K
.
Examples
use std::collections::HashMap; let mut map = HashMap::new(); map.insert("a", 1); map.insert("b", 2); map.insert("c", 3); for key in map.keys() { println!("{}", key); }Run
ⓘImportant traits for Values<'a, K, V>pub fn values(&self) -> Values<K, V>
[src]
An iterator visiting all values in arbitrary order.
The iterator element type is &'a V
.
Examples
use std::collections::HashMap; let mut map = HashMap::new(); map.insert("a", 1); map.insert("b", 2); map.insert("c", 3); for val in map.values() { println!("{}", val); }Run
ⓘImportant traits for ValuesMut<'a, K, V>pub fn values_mut(&mut self) -> ValuesMut<K, V>
1.10.0[src]
An iterator visiting all values mutably in arbitrary order.
The iterator element type is &'a mut V
.
Examples
use std::collections::HashMap; let mut map = HashMap::new(); map.insert("a", 1); map.insert("b", 2); map.insert("c", 3); for val in map.values_mut() { *val = *val + 10; } for val in map.values() { println!("{}", val); }Run
ⓘImportant traits for Iter<'a, K, V>pub fn iter(&self) -> Iter<K, V>
[src]
An iterator visiting all key-value pairs in arbitrary order.
The iterator element type is (&'a K, &'a V)
.
Examples
use std::collections::HashMap; let mut map = HashMap::new(); map.insert("a", 1); map.insert("b", 2); map.insert("c", 3); for (key, val) in map.iter() { println!("key: {} val: {}", key, val); }Run
ⓘImportant traits for IterMut<'a, K, V>pub fn iter_mut(&mut self) -> IterMut<K, V>
[src]
An iterator visiting all key-value pairs in arbitrary order,
with mutable references to the values.
The iterator element type is (&'a K, &'a mut V)
.
Examples
use std::collections::HashMap; let mut map = HashMap::new(); map.insert("a", 1); map.insert("b", 2); map.insert("c", 3); // Update all values for (_, val) in map.iter_mut() { *val *= 2; } for (key, val) in &map { println!("key: {} val: {}", key, val); }Run
pub fn len(&self) -> usize
[src]
Returns the number of elements in the map.
Examples
use std::collections::HashMap; let mut a = HashMap::new(); assert_eq!(a.len(), 0); a.insert(1, "a"); assert_eq!(a.len(), 1);Run
pub fn is_empty(&self) -> bool
[src]
Returns true
if the map contains no elements.
Examples
use std::collections::HashMap; let mut a = HashMap::new(); assert!(a.is_empty()); a.insert(1, "a"); assert!(!a.is_empty());Run
ⓘImportant traits for Drain<'a, K, V>pub fn drain(&mut self) -> Drain<K, V>
1.6.0[src]
Clears the map, returning all key-value pairs as an iterator. Keeps the allocated memory for reuse.
Examples
use std::collections::HashMap; let mut a = HashMap::new(); a.insert(1, "a"); a.insert(2, "b"); for (k, v) in a.drain().take(1) { assert!(k == 1 || k == 2); assert!(v == "a" || v == "b"); } assert!(a.is_empty());Run
pub fn clear(&mut self)
[src]
impl<K, V, S> HashMap<K, V, S> where
K: Eq + Hash,
S: BuildHasher,
[src]
K: Eq + Hash,
S: BuildHasher,
pub fn with_hasher(hash_builder: S) -> HashMap<K, V, S>
1.7.0[src]
Creates an empty HashMap
which will use the given hash builder to hash
keys.
The created map has the default initial capacity.
Warning: hash_builder
is normally randomly generated, and
is designed to allow HashMaps to be resistant to attacks that
cause many collisions and very poor performance. Setting it
manually using this function can expose a DoS attack vector.
Examples
use std::collections::HashMap; use std::collections::hash_map::RandomState; let s = RandomState::new(); let mut map = HashMap::with_hasher(s); map.insert(1, 2);Run
pub fn with_capacity_and_hasher(
capacity: usize,
hash_builder: S
) -> HashMap<K, V, S>
1.7.0[src]
capacity: usize,
hash_builder: S
) -> HashMap<K, V, S>
Creates an empty HashMap
with the specified capacity, using hash_builder
to hash the keys.
The hash map will be able to hold at least capacity
elements without
reallocating. If capacity
is 0, the hash map will not allocate.
Warning: hash_builder
is normally randomly generated, and
is designed to allow HashMaps to be resistant to attacks that
cause many collisions and very poor performance. Setting it
manually using this function can expose a DoS attack vector.
Examples
use std::collections::HashMap; use std::collections::hash_map::RandomState; let s = RandomState::new(); let mut map = HashMap::with_capacity_and_hasher(10, s); map.insert(1, 2);Run
ⓘImportant traits for &'_ mut Fpub fn hasher(&self) -> &S
1.9.0[src]
Returns a reference to the map's BuildHasher
.
Examples
use std::collections::HashMap; use std::collections::hash_map::RandomState; let hasher = RandomState::new(); let map: HashMap<i32, i32> = HashMap::with_hasher(hasher); let hasher: &RandomState = map.hasher();Run
pub fn reserve(&mut self, additional: usize)
[src]
Reserves capacity for at least additional
more elements to be inserted
in the HashMap
. The collection may reserve more space to avoid
frequent reallocations.
Panics
Panics if the new allocation size overflows usize
.
Examples
use std::collections::HashMap; let mut map: HashMap<&str, i32> = HashMap::new(); map.reserve(10);Run
pub fn try_reserve(&mut self, additional: usize) -> Result<(), TryReserveError>
[src]
🔬 This is a nightly-only experimental API. (try_reserve
#48043)
new API
Tries to reserve capacity for at least additional
more elements to be inserted
in the given HashMap<K,V>
. The collection may reserve more space to avoid
frequent reallocations.
Errors
If the capacity overflows, or the allocator reports a failure, then an error is returned.
Examples
#![feature(try_reserve)] use std::collections::HashMap; let mut map: HashMap<&str, isize> = HashMap::new(); map.try_reserve(10).expect("why is the test harness OOMing on 10 bytes?");Run
pub fn shrink_to_fit(&mut self)
[src]
Shrinks the capacity of the map as much as possible. It will drop down as much as possible while maintaining the internal rules and possibly leaving some space in accordance with the resize policy.
Examples
use std::collections::HashMap; let mut map: HashMap<i32, i32> = HashMap::with_capacity(100); map.insert(1, 2); map.insert(3, 4); assert!(map.capacity() >= 100); map.shrink_to_fit(); assert!(map.capacity() >= 2);Run
pub fn shrink_to(&mut self, min_capacity: usize)
[src]
🔬 This is a nightly-only experimental API. (shrink_to
#56431)
new API
Shrinks the capacity of the map with a lower limit. It will drop down no lower than the supplied limit while maintaining the internal rules and possibly leaving some space in accordance with the resize policy.
Panics if the current capacity is smaller than the supplied minimum capacity.
Examples
#![feature(shrink_to)] use std::collections::HashMap; let mut map: HashMap<i32, i32> = HashMap::with_capacity(100); map.insert(1, 2); map.insert(3, 4); assert!(map.capacity() >= 100); map.shrink_to(10); assert!(map.capacity() >= 10); map.shrink_to(0); assert!(map.capacity() >= 2);Run
pub fn entry(&mut self, key: K) -> Entry<K, V>
[src]
Gets the given key's corresponding entry in the map for in-place manipulation.
Examples
use std::collections::HashMap; let mut letters = HashMap::new(); for ch in "a short treatise on fungi".chars() { let counter = letters.entry(ch).or_insert(0); *counter += 1; } assert_eq!(letters[&'s'], 2); assert_eq!(letters[&'t'], 3); assert_eq!(letters[&'u'], 1); assert_eq!(letters.get(&'y'), None);Run
pub fn get<Q: ?Sized>(&self, k: &Q) -> Option<&V> where
K: Borrow<Q>,
Q: Hash + Eq,
[src]
K: Borrow<Q>,
Q: Hash + Eq,
Returns a reference to the value corresponding to the key.
The key may be any borrowed form of the map's key type, but
Hash
and Eq
on the borrowed form must match those for
the key type.
Examples
use std::collections::HashMap; let mut map = HashMap::new(); map.insert(1, "a"); assert_eq!(map.get(&1), Some(&"a")); assert_eq!(map.get(&2), None);Run
pub fn get_key_value<Q: ?Sized>(&self, k: &Q) -> Option<(&K, &V)> where
K: Borrow<Q>,
Q: Hash + Eq,
[src]
K: Borrow<Q>,
Q: Hash + Eq,
Returns the key-value pair corresponding to the supplied key.
The supplied key may be any borrowed form of the map's key type, but
Hash
and Eq
on the borrowed form must match those for
the key type.
Examples
#![feature(map_get_key_value)] use std::collections::HashMap; let mut map = HashMap::new(); map.insert(1, "a"); assert_eq!(map.get_key_value(&1), Some((&1, &"a"))); assert_eq!(map.get_key_value(&2), None);Run
pub fn contains_key<Q: ?Sized>(&self, k: &Q) -> bool where
K: Borrow<Q>,
Q: Hash + Eq,
[src]
K: Borrow<Q>,
Q: Hash + Eq,
Returns true
if the map contains a value for the specified key.
The key may be any borrowed form of the map's key type, but
Hash
and Eq
on the borrowed form must match those for
the key type.
Examples
use std::collections::HashMap; let mut map = HashMap::new(); map.insert(1, "a"); assert_eq!(map.contains_key(&1), true); assert_eq!(map.contains_key(&2), false);Run
pub fn get_mut<Q: ?Sized>(&mut self, k: &Q) -> Option<&mut V> where
K: Borrow<Q>,
Q: Hash + Eq,
[src]
K: Borrow<Q>,
Q: Hash + Eq,
Returns a mutable reference to the value corresponding to the key.
The key may be any borrowed form of the map's key type, but
Hash
and Eq
on the borrowed form must match those for
the key type.
Examples
use std::collections::HashMap; let mut map = HashMap::new(); map.insert(1, "a"); if let Some(x) = map.get_mut(&1) { *x = "b"; } assert_eq!(map[&1], "b");Run
pub fn insert(&mut self, k: K, v: V) -> Option<V>
[src]
Inserts a key-value pair into the map.
If the map did not have this key present, None
is returned.
If the map did have this key present, the value is updated, and the old
value is returned. The key is not updated, though; this matters for
types that can be ==
without being identical. See the module-level
documentation for more.
Examples
use std::collections::HashMap; let mut map = HashMap::new(); assert_eq!(map.insert(37, "a"), None); assert_eq!(map.is_empty(), false); map.insert(37, "b"); assert_eq!(map.insert(37, "c"), Some("b")); assert_eq!(map[&37], "c");Run
pub fn remove<Q: ?Sized>(&mut self, k: &Q) -> Option<V> where
K: Borrow<Q>,
Q: Hash + Eq,
[src]
K: Borrow<Q>,
Q: Hash + Eq,
Removes a key from the map, returning the value at the key if the key was previously in the map.
The key may be any borrowed form of the map's key type, but
Hash
and Eq
on the borrowed form must match those for
the key type.
Examples
use std::collections::HashMap; let mut map = HashMap::new(); map.insert(1, "a"); assert_eq!(map.remove(&1), Some("a")); assert_eq!(map.remove(&1), None);Run
pub fn remove_entry<Q: ?Sized>(&mut self, k: &Q) -> Option<(K, V)> where
K: Borrow<Q>,
Q: Hash + Eq,
1.27.0[src]
K: Borrow<Q>,
Q: Hash + Eq,
Removes a key from the map, returning the stored key and value if the key was previously in the map.
The key may be any borrowed form of the map's key type, but
Hash
and Eq
on the borrowed form must match those for
the key type.
Examples
use std::collections::HashMap; let mut map = HashMap::new(); map.insert(1, "a"); assert_eq!(map.remove_entry(&1), Some((1, "a"))); assert_eq!(map.remove(&1), None);Run
pub fn retain<F>(&mut self, f: F) where
F: FnMut(&K, &mut V) -> bool,
1.18.0[src]
F: FnMut(&K, &mut V) -> bool,
Retains only the elements specified by the predicate.
In other words, remove all pairs (k, v)
such that f(&k,&mut v)
returns false
.
Examples
use std::collections::HashMap; let mut map: HashMap<i32, i32> = (0..8).map(|x|(x, x*10)).collect(); map.retain(|&k, _| k % 2 == 0); assert_eq!(map.len(), 4);Run
impl<K, V, S> HashMap<K, V, S> where
S: BuildHasher,
[src]
S: BuildHasher,
pub fn raw_entry_mut(&mut self) -> RawEntryBuilderMut<K, V, S>
[src]
Creates a raw entry builder for the HashMap.
Raw entries provide the lowest level of control for searching and manipulating a map. They must be manually initialized with a hash and then manually searched. After this, insertions into a vacant entry still require an owned key to be provided.
Raw entries are useful for such exotic situations as:
- Hash memoization
- Deferring the creation of an owned key until it is known to be required
- Using a search key that doesn't work with the Borrow trait
- Using custom comparison logic without newtype wrappers
Because raw entries provide much more low-level control, it's much easier
to put the HashMap into an inconsistent state which, while memory-safe,
will cause the map to produce seemingly random results. Higher-level and
more foolproof APIs like entry
should be preferred when possible.
In particular, the hash used to initialized the raw entry must still be consistent with the hash of the key that is ultimately stored in the entry. This is because implementations of HashMap may need to recompute hashes when resizing, at which point only the keys are available.
Raw entries give mutable access to the keys. This must not be used to modify how the key would compare or hash, as the map will not re-evaluate where the key should go, meaning the keys may become "lost" if their location does not reflect their state. For instance, if you change a key so that the map now contains keys which compare equal, search may start acting erratically, with two keys randomly masking each other. Implementations are free to assume this doesn't happen (within the limits of memory-safety).
pub fn raw_entry(&self) -> RawEntryBuilder<K, V, S>
[src]
Creates a raw immutable entry builder for the HashMap.
Raw entries provide the lowest level of control for searching and manipulating a map. They must be manually initialized with a hash and then manually searched.
This is useful for
- Hash memoization
- Using a search key that doesn't work with the Borrow trait
- Using custom comparison logic without newtype wrappers
Unless you are in such a situation, higher-level and more foolproof APIs like
get
should be preferred.
Immutable raw entries have very limited use; you might instead want raw_entry_mut
.
Trait Implementations
impl<K, V, S> UnwindSafe for HashMap<K, V, S> where
K: UnwindSafe,
V: UnwindSafe,
S: UnwindSafe,
1.36.0[src]
K: UnwindSafe,
V: UnwindSafe,
S: UnwindSafe,
impl<K, V, S> PartialEq<HashMap<K, V, S>> for HashMap<K, V, S> where
K: Eq + Hash,
V: PartialEq,
S: BuildHasher,
[src]
K: Eq + Hash,
V: PartialEq,
S: BuildHasher,
fn eq(&self, other: &HashMap<K, V, S>) -> bool
[src]
#[must_use]
fn ne(&self, other: &Rhs) -> bool
[src]
impl<K, V, S> Eq for HashMap<K, V, S> where
K: Eq + Hash,
V: Eq,
S: BuildHasher,
[src]
K: Eq + Hash,
V: Eq,
S: BuildHasher,
impl<'_, K, Q: ?Sized, V, S> Index<&'_ Q> for HashMap<K, V, S> where
K: Eq + Hash + Borrow<Q>,
Q: Eq + Hash,
S: BuildHasher,
[src]
K: Eq + Hash + Borrow<Q>,
Q: Eq + Hash,
S: BuildHasher,
type Output = V
The returned type after indexing.
ⓘImportant traits for &'_ mut Ffn index(&self, key: &Q) -> &V
[src]
Returns a reference to the value corresponding to the supplied key.
Panics
Panics if the key is not present in the HashMap
.
impl<K, V, S> Debug for HashMap<K, V, S> where
K: Eq + Hash + Debug,
V: Debug,
S: BuildHasher,
[src]
K: Eq + Hash + Debug,
V: Debug,
S: BuildHasher,
impl<K, V, S> FromIterator<(K, V)> for HashMap<K, V, S> where
K: Eq + Hash,
S: BuildHasher + Default,
[src]
K: Eq + Hash,
S: BuildHasher + Default,
impl<'a, K, V, S> IntoIterator for &'a HashMap<K, V, S>
[src]
type Item = (&'a K, &'a V)
The type of the elements being iterated over.
type IntoIter = Iter<'a, K, V>
Which kind of iterator are we turning this into?
ⓘImportant traits for Iter<'a, K, V>fn into_iter(self) -> Iter<'a, K, V>
[src]
impl<'a, K, V, S> IntoIterator for &'a mut HashMap<K, V, S>
[src]
type Item = (&'a K, &'a mut V)
The type of the elements being iterated over.
type IntoIter = IterMut<'a, K, V>
Which kind of iterator are we turning this into?
ⓘImportant traits for IterMut<'a, K, V>fn into_iter(self) -> IterMut<'a, K, V>
[src]
impl<K, V, S> IntoIterator for HashMap<K, V, S>
[src]
type Item = (K, V)
The type of the elements being iterated over.
type IntoIter = IntoIter<K, V>
Which kind of iterator are we turning this into?
ⓘImportant traits for IntoIter<K, V>fn into_iter(self) -> IntoIter<K, V>
[src]
Creates a consuming iterator, that is, one that moves each key-value pair out of the map in arbitrary order. The map cannot be used after calling this.
Examples
use std::collections::HashMap; let mut map = HashMap::new(); map.insert("a", 1); map.insert("b", 2); map.insert("c", 3); // Not possible with .iter() let vec: Vec<(&str, i32)> = map.into_iter().collect();Run
impl<K, V, S> Extend<(K, V)> for HashMap<K, V, S> where
K: Eq + Hash,
S: BuildHasher,
[src]
K: Eq + Hash,
S: BuildHasher,
fn extend<T: IntoIterator<Item = (K, V)>>(&mut self, iter: T)
[src]
impl<'a, K, V, S> Extend<(&'a K, &'a V)> for HashMap<K, V, S> where
K: Eq + Hash + Copy,
V: Copy,
S: BuildHasher,
1.4.0[src]
K: Eq + Hash + Copy,
V: Copy,
S: BuildHasher,
impl<K: Clone, V: Clone, S: Clone> Clone for HashMap<K, V, S>
[src]
impl<K, V, S> Default for HashMap<K, V, S> where
K: Eq + Hash,
S: BuildHasher + Default,
[src]
K: Eq + Hash,
S: BuildHasher + Default,
Auto Trait Implementations
impl<K, V, S> RefUnwindSafe for HashMap<K, V, S> where
K: RefUnwindSafe,
S: RefUnwindSafe,
V: RefUnwindSafe,
K: RefUnwindSafe,
S: RefUnwindSafe,
V: RefUnwindSafe,
impl<K, V, S> Unpin for HashMap<K, V, S> where
K: Unpin,
S: Unpin,
V: Unpin,
K: Unpin,
S: Unpin,
V: Unpin,
impl<K, V, S> Send for HashMap<K, V, S> where
K: Send,
S: Send,
V: Send,
K: Send,
S: Send,
V: Send,
impl<K, V, S> Sync for HashMap<K, V, S> where
K: Sync,
S: Sync,
V: Sync,
K: Sync,
S: Sync,
V: Sync,
Blanket Implementations
impl<T> From<T> for T
[src]
impl<T, U> TryFrom<U> for T where
U: Into<T>,
[src]
U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
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impl<I> IntoIterator for I where
I: Iterator,
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I: Iterator,
type Item = <I as Iterator>::Item
The type of the elements being iterated over.
type IntoIter = I
Which kind of iterator are we turning this into?
fn into_iter(self) -> I
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impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
ⓘImportant traits for &'_ mut Ffn borrow_mut(&mut self) -> &mut T
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impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> ToOwned for T where
T: Clone,
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T: Clone,