What is the more idiomatic way to sort a vector of strings by char?
Example:
Input:
["3r", "2n", "2s", "7r", "1s", "1s", "6r", "1s", "1n", "1n", "5n", "9n", "3r"]
Desired output:
["1n", "1n", "2n", "5n", "9n, "3r", "3r", "6r", "7r", "1s", "1s", "1s", "2s"]
首先，需要根据第二个字符对它们进行排序，以便将它们分组在一起，然后按第一个字符进行排序.
我用.filter和.sort_by试了很多方法，但都不成功.
如果字符串的长度始终为两个字符，并且您总是希望首先按第二个字符对它们进行排序，则可以使用.sort_by作为比较器，该比较器会反转查看字符串:
let mut input = vec!("3r", "2n", "2s", "7r", "1s", "1s", "6r", "1s", "1n", "1n", "5n", "9n", "3r");
input.sort_by(|a, b| a.chars().rev().cmp(b.chars().rev()));
let expected = vec!("1n", "1n", "2n", "5n", "9n", "3r", "3r", "6r", "7r", "1s", "1s", "1s", "2s");
assert!(input == expected);