Generate permutaion and combination

permutation_combination.py

def permutation(array):
    if len(array) == 1:
        return [array]
    output = []
    for i in range(len(array)):
        if i == len(array) - 1:
            remain = array[0:i]
        else:
            remain = array[0:i] + array[i+1:]
        for back in permutation(remain):
            output.append([array[i]] + back)
    return output
    
    
def combine(array, n):
    if len(array) == n:
        return [array]
    elif n == 0:
        return []
    output = []
    for i in range(len(array) - n + 1):
        remain = array[i+1:]
        if n - 1 == 0:
            output.append([array[i]])
        else:
            for r in combine(remain, n-1):
                output.append([array[i]] + r)
    return output
    
    
array = [1, 2, 3, 4]
for line in permutation(array):
    print(line)


A = [2, 3, 5, 2]
for line in combine(A, 2):
    print(line)