How to mathematically subtract two lists in python? [duplicate]

Answer 1

Try something like

def substract_lists(a, b):
    for i, val in enumerate(a):
            val = val - b[i]
    return a

Answer 2

You can use zip and a list comprehension:

>>> A = [3, 4, 6, 7]
>>> B = [1, 3, 6, 3]
>>> zip(A, B) # Just to demonstrate
[(3, 1), (4, 3), (6, 6), (7, 3)]
>>> [x - y for x, y in zip(A, B)]
[2, 1, 0, 4]
>>>

Answer 3

Use operator with map module:

>>> A = [3, 4, 6, 7]
>>> B = [1, 3, 6, 3]
>>> map(operator.sub, A, B)
[2, 1, 0, 4]

As @SethMMorton mentioned below, in Python 3, you need this instead

>>> A = [3, 4, 6, 7]
>>> B = [1, 3, 6, 3]
>>> list(map(operator.sub, A, B))
[2, 1, 0, 4]

Because, map in Python returns an iterator instead.