Generate all combinations based on a combination of mandatory and optional parts

script.py

import numpy as np

line = "mandatory1(optional1)mandatory2(optional2)(optional3)"
# use regex or a char by char stack approach to extract these?
parts = ["mandatory1", "optional1", "mandatory2", "optional2", "optional3"]
fixPositions = [0, 2]

elements = len(parts)
optionalElements = elements - len(fixPositions)
n = 2 ** optionalElements

print(elements, "elements in total:", len(fixPositions), "fix,", optionalElements, "optional --> generating", n, "options")

# via https://www.w3resource.com/python-exercises/numpy/python-numpy-exercise-187.php
matrix = (((np.arange(n).reshape(-1, 1) & (2 ** np.arange(optionalElements))) != 0).astype(int))[:, ::-1]

for fixPos in fixPositions:
    insertCol = np.full((n, 1), 1)
    # via https://stackoverflow.com/a/40825989, use pandas instead?
    matrix = np.hstack((matrix[:, :fixPos], insertCol, matrix[:, fixPos:]))

# print(matrix)

for r in range(n):
    row = matrix[r]
    branch = []
    for c in range(elements):
        if row[c] == 1:
            branch.append(parts[c])
    print(branch)

Output:

['mandatory1', 'mandatory2']
['mandatory1', 'mandatory2', 'optional3']
['mandatory1', 'mandatory2', 'optional2']
['mandatory1', 'mandatory2', 'optional2', 'optional3']
['mandatory1', 'optional1', 'mandatory2']
['mandatory1', 'optional1', 'mandatory2', 'optional3']
['mandatory1', 'optional1', 'mandatory2', 'optional2']
['mandatory1', 'optional1', 'mandatory2', 'optional2', 'optional3']