count-invert

count-invert is a Rust crate providing utility functions for counting the occurrences of elements in a vector and inverting a HashMap based on those counts. This crate leverages the itertools crate to offer robust and efficient functionalities for common data manipulation tasks.

Features

Convert a vector into a HashMap with element counts.
Invert a HashMap to map counts to vectors of elements.
Combine both functionalities to create a HashMap mapping counts to vectors of elements directly from a vector.

Installation

Add count-invert to your Cargo.toml:

[dependencies]
count-invert = "0.1.0"

Usage

Here's how to use the count-invert crate:

into_counts Convert a vector into a HashMap where the keys are the elements and the values are their counts.

use count_invert::into_counts;
use std::collections::HashMap;

let vec = vec![1, 2, 2, 3, 3, 3];
let counts: HashMap<i32, usize> = into_counts(vec);
println!("{:?}", counts); // Output: {1: 1, 2: 2, 3: 3}

invert_map Invert a HashMap such that the keys become the values and the values become the keys.

use count_invert::invert_map;
use std::collections::HashMap;

let mut map = HashMap::new();
map.insert(1, 2);
map.insert(2, 2);
map.insert(3, 3);

let inverted: HashMap<usize, Vec<i32>> = invert_map(map);
println!("{:?}", inverted); // Output: {2: [1, 2], 3: [3]}

into_count_map Convert a vector into a HashMap where the keys are the counts of elements and the values are vectors of elements with those counts.

use count_invert::into_count_map;
use std::collections::HashMap;

let vec = vec![1, 2, 2, 3, 3, 3];
let count_map: HashMap<usize, Vec<i32>> = into_count_map(vec);
println!("{:?}", count_map); // Output: {1: [1], 2: [2], 3: [3]}

Contributing

Contributions are welcome! Please submit pull requests or open issues to suggest improvements or report bugs.

License