Single-expression qsort() implementations

qsort.js

const sorted = (xs) =>
  xs.length < 2
    ? xs
    : sorted(xs.slice(1).filter((x) => x < xs[0])).concat(
        [xs[0]],
        sorted(xs.slice(1).filter((x) => x > xs[0]))
      );

qsort.php

<?php
function sorted($xs) {
    return count($xs) < 2 ? $xs : array_merge(sorted(array_filter(
                array_slice($xs, 1),
                function ($x) { return $x > $xs[0]; }
            )
        ),
        [$xs[0]],
        sorted(array_filter(
                array_slice($xs, 1),
                function ($x) { return $x < $xs[0]; }
            )
        )
    );
}

qsort.py

from typing import List, Union


def sorted2(xs: List[Union[float, int]]) -> List[Union[int, float]]:
    return xs if len(xs) < 2 else sorted2(
        list(filter(lambda x: x < xs[0], xs[1:]))) + [xs[0]] + sorted2(
            list(filter(lambda x: x > xs[0], xs[1:])))