A 'quick' implementation of the recursive quicksort.

qsort.py

""" Two python implementations of the quicksort algorithm."""
__all__ = ["sort_np", "sort_pure"]
import numpy as np


def sort_np(array):
    """ For numpy arrays, with masking. """
    if len(array) <= 1:
        return array
    pivot = array[0]
    less_than = array[array < pivot]
    equal = array[array == pivot]
    more_than = array[array > pivot]
    less_than = sort_np(less_than)
    more_than = sort_np(more_than)
    array = np.append(less_than, equal)
    array = np.append(array, more_than)
    return array


def sort_pure(array):
    """ Using builtin list comprehension. """
    if len(array) < 1:
        return array
    pivot = array[0]
    less = [number for number in array if number < pivot]
    more = [number for number in array if number > pivot]
    equal = [number for number in array if number == pivot]
    array = sort_pure(less) + equal + sort_pure(more)
    return array