Struct near_sdk::store::tree_map::TreeMap

source · 
pub struct TreeMap<K, V, H = Sha256>where
    K: BorshSerialize + Ord,
    V: BorshSerialize,
    H: ToKey,{ /* private fields */ }
Expand description

TreeMap based on AVL-tree

Runtime complexity (worst case):

  • get/contains_key: O(1) - LookupMap lookup
  • insert/remove: O(log(N))
  • min/max: O(log(N))
  • above/below: O(log(N))
  • range of K elements: O(Klog(N))

Implementations

Initialize new TreeMap with the prefix provided.

This prefix can be anything that implements IntoStorageKey. The prefix is used when storing and looking up values in storage to ensure no collisions with other collections.

Return the amount of elements inside of the map.

Returns true if there are no elements inside of the map.

Clears the map, removing all key-value pairs. Keeps the allocated memory for reuse.

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 BorshSerialize and ToOwned<Owned = K> on the borrowed form must match those for the key type.

Returns a reference to the value corresponding to the key.

The key may be any borrowed form of the map’s key type, but BorshSerialize and ToOwned<Owned = K> on the borrowed form must match those for the key type.

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 the ordering on the borrowed form must match the ordering on the key type.

Examples
use near_sdk::store::TreeMap;

let mut map = TreeMap::new(b"t");
map.insert(1, "a".to_string());
assert_eq!(map.get_key_value(&1), Some((&1, &"a".to_string())));
assert_eq!(map.get_key_value(&2), None);

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 BorshSerialize and ToOwned<Owned = K> on the borrowed form must match those for the key type.

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.

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 BorshSerialize and ToOwned<Owned = K> on the borrowed form must match those for the key type.

An iterator visiting all key-value pairs in arbitrary order. The iterator element type is (&'a K, &'a V).

An iterator visiting all key-value pairs in arbitrary order, with exclusive references to the values. The iterator element type is (&'a K, &'a mut V).

An iterator visiting all keys in arbitrary order. The iterator element type is &'a K.

An iterator visiting all values in arbitrary order. The iterator element type is &'a V.

A mutable iterator visiting all values in arbitrary order. The iterator element type is &'a mut V.

Constructs a double-ended iterator over a sub-range of elements in the map. The simplest way is to use the range syntax min..max, thus range(min..max) will yield elements from min (inclusive) to max (exclusive). The range may also be entered as (Bound<T>, Bound<T>), so for example range((Excluded(4), Included(10))) will yield a left-exclusive, right-inclusive range from 4 to 10.

Panics

Panics if range start > end. Panics if range start == end and both bounds are Excluded.

Examples

Basic usage:

use near_sdk::store::TreeMap;
use std::ops::Bound::Included;

let mut map = TreeMap::new(b"t");
map.insert(3, "a".to_string());
map.insert(5, "b".to_string());
map.insert(8, "c".to_string());
for (key, value) in map.range((Included(&4), Included(&8))) {
    println!("{}: {}", key, value);
}
assert_eq!(Some((&5, &"b".to_string())), map.range(4..).next());

Constructs a mutable double-ended iterator over a sub-range of elements in the map. The simplest way is to use the range syntax min..max, thus range(min..max) will yield elements from min (inclusive) to max (exclusive). The range may also be entered as (Bound<T>, Bound<T>), so for example range((Excluded(4), Included(10))) will yield a left-exclusive, right-inclusive range from 4 to 10.

Panics

Panics if range start > end. Panics if range start == end and both bounds are Excluded.

Examples

Basic usage:

use near_sdk::store::TreeMap;

let mut map: TreeMap<i32, i32> = TreeMap::new(b"t");
map.extend([4, 6, 8, 11]
    .iter()
    .map(|&s| (s, 0)));
for (_, balance) in map.range_mut(6..10) {
    *balance += 100;
}
for (id, balance) in &map {
    println!("{} => {}", id, balance);
}
source

pub fn remove_entry<Q: ?Sized>(&mut self, key: &Q) -> Option<(K, V)>where
    K: Borrow<Q> + BorshDeserialize + Clone,
    Q: BorshSerialize + ToOwned<Owned = K> + Eq + PartialOrd,

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 BorshSerialize and ToOwned<Owned = K> on the borrowed form must match those for the key type.

Examples
use near_sdk::store::TreeMap;

let mut map = TreeMap::new(b"m");
map.insert(1, "a".to_string());
assert_eq!(map.remove(&1), Some("a".to_string()));
assert_eq!(map.remove(&1), None);

Gets the given key’s corresponding entry in the map for in-place manipulation.

use near_sdk::store::TreeMap;

let mut count = TreeMap::new(b"m");

for ch in [7, 2, 4, 7, 4, 1, 7] {
    let counter = count.entry(ch).or_insert(0);
    *counter += 1;
}

assert_eq!(count[&4], 2);
assert_eq!(count[&7], 3);
assert_eq!(count[&1], 1);
assert_eq!(count.get(&8), None);

Flushes the intermediate values of the map before this is called when the structure is Droped. This will write all modified values to storage but keep all cached values in memory.

Trait Implementations

Deserializes this instance from a given slice of bytes. Updates the buffer to point at the remaining bytes. Read more
Deserialize this instance from a slice of bytes.
Serialize this instance into a vector of bytes.
Formats the value using the given formatter. 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

Returns reference to value corresponding to key.

Panics

Panics if the key does not exist in the map

The returned type after indexing.
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

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

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

Should always be Self
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.