Function std::cmp::min_by_key

pub fn min_by_key<T, F, K>(v1: T, v2: T, f: F) -> T where    F: FnMut(&T) -> K,    K: Ord, 

Returns the element that gives the minimum value from the specified function.

Returns the first argument if the comparison determines them to be equal.

Examples

#![feature(cmp_min_max_by)]

use std::cmp;

assert_eq!(cmp::min_by_key(-2, 1, |x: &i32| x.abs()), 1);
assert_eq!(cmp::min_by_key(-2, 2, |x: &i32| x.abs()), -2);