[][src]Crate indexmap

IndexMap is a hash table where the iteration order of the key-value pairs is independent of the hash values of the keys.

IndexSet is a corresponding hash set using the same implementation and with similar properties.

Feature Highlights

IndexMap and IndexSet are drop-in compatible with the std HashMap and HashSet, but they also have some features of note:

Alternate Hashers

IndexMap and IndexSet have a default hasher type S = RandomState, just like the standard HashMap and HashSet, which is resistant to HashDoS attacks but not the most performant. Type aliases can make it easier to use alternate hashers:

use fnv::FnvBuildHasher;
use fxhash::FxBuildHasher;
use indexmap::{IndexMap, IndexSet};

type FnvIndexMap<K, V> = IndexMap<K, V, FnvBuildHasher>;
type FnvIndexSet<T> = IndexSet<T, FnvBuildHasher>;

type FxIndexMap<K, V> = IndexMap<K, V, FxBuildHasher>;
type FxIndexSet<T> = IndexSet<T, FxBuildHasher>;

let std: IndexSet<i32> = (0..100).collect();
let fnv: FnvIndexSet<i32> = (0..100).collect();
let fx: FxIndexSet<i32> = (0..100).collect();
assert_eq!(std, fnv);
assert_eq!(std, fx);

Rust Version

This version of indexmap requires Rust 1.49 or later.

The indexmap 1.x release series will use a carefully considered version upgrade policy, where in a later 1.x version, we will raise the minimum required Rust version.

No Standard Library Targets

This crate supports being built without std, requiring alloc instead. This is enabled automatically when it is detected that std is not available. There is no crate feature to enable/disable to trigger this. It can be tested by building for a std-less target.

Re-exports

pub use crate::map::IndexMap;
pub use crate::set::IndexSet;

Modules

map

IndexMap is a hash table where the iteration order of the key-value pairs is independent of the hash values of the keys.

set

A hash set implemented using IndexMap

Macros

indexmap

Create an IndexMap from a list of key-value pairs

indexset

Create an IndexSet from a list of values

Traits

Equivalent

Key equivalence trait.