Crate bimap

A fast two-way bijective map.

A Bimap<L, R> is a bijective map between values of type L, called left values, and values of type R, called right values. This means every left value is associated with exactly one right value and vice versa. Compare this to a HashMap<K, V>, where every key is associated with exactly one value but a value can be associated with more than one key.

Internally, a Bimap is composed of two HashMaps, one for the left-to-right direction and one for right-to-left. As such, the big-O performance of the get(), remove(), insert(), and contains() functions are the same as those of a HashMap.

As with HashMap, it is considered a logic error to modify a value's hash while it is in the Bimap using a Cell, RefCell, etc.

Examples

use bimap::Bimap;

let mut elements = Bimap::new();

// insert chemicals and their corresponding symbols
elements.insert("hydrogen", "H");
elements.insert("carbon", "C");
elements.insert("bromine", "Br");
elements.insert("neodymium", "Nd");

// retrieve chemical symbol by name (left to right)
assert_eq!(elements.get_by_left(&"bromine"), Some(&"Br"));
assert_eq!(elements.get_by_left(&"oxygen"), None);

// retrieve name by chemical symbol (right to left)
assert_eq!(elements.get_by_right(&"C"), Some(&"carbon"));
assert_eq!(elements.get_by_right(&"Al"), None);

// check membership
assert!(elements.contains_left(&"hydrogen"));
assert!(!elements.contains_right(&"He"));

// remove elements
assert_eq!(elements.remove_by_left(&"neodymium"), Some(("neodymium", "Nd")));
assert_eq!(elements.remove_by_right(&"Nd"), None);

// iterate over elements
for (left, right) in &elements {
    println!("the chemical symbol for {} is {}", left, right);
}

Structs

Bimap	A two-way map between left values and right values.
IntoIter	An owning iterator over the left-right pairs in a Bimap.
Iter	An iterator over the left-right pairs in a Bimap.
LeftValues	An iterator over the left values in a Bimap.
RightValues	An iterator over the right values in a Bimap.

Enums

Overwritten

The previous left-right pairs, if any, that were overwritten by a call to bimap.insert().