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

Usage

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

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

Import both Frequency and BTreeMapFrequency:

extern crate frequency;
extern crate frequency_btreemap;

use frequency::Frequency;
use frequency_btreemap::BTreeMapFrequency;