Function std::cmp::max_by_key

pub fn max_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 maximum value from the specified function.

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

Examples

use std::cmp;

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