The Frequency trait represents types that keep track of the observed counts of items. The HashMapFrequency type is a frequency counter backed by a HashMap.

Usage

Add frequency and frequency-hashmap to your Cargo.toml:

[dependencies]
frequency = "^1.0.0"
frequency-hashmap = "^1.0.0"

Import both Frequency and HashMapFrequency:

extern crate frequency;
extern crate frequency_hashmap;

use frequency::Frequency;
use frequency_hashmap::HashMapFrequency;