Struct solana_sdk::feature_set::FEATURE_NAMES [−][src]
pub struct FEATURE_NAMES { /* fields omitted */ }
Expand description
Map of feature identifiers to user-visible description
Methods from Deref<Target = HashMap<Pubkey, &'static str>>
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);
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); }
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); }
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); }
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);
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());
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();
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);
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
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);
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);
🔬 This is a nightly-only experimental API. (hash_raw_entry
)
hash_raw_entry
)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
.