I'm doing Codewars and got stuck at this simple question. The question was:
Your goal in this kata is to implement a difference function, which subtracts one list from another and returns the result. It should remove all values from list a, which are present in list b keeping their order. If a value is present in b, all of its occurrences must be removed from the other.
This is what I've tried:
def array_diff(a, b):
if a == []: return b
if b == []: return a
for occurrence in b:
if occurrence in a:
a.remove(occurrence)
return a
and for some reason I got 2 failed tests, the requirements for those failed tests are:
a was [1,2,2], b was [2], expected [1]: [1, 2] should equal [1]
a was [], b was [1,2], expected []: [1, 2] should equal []
can anyone help me and also explain if possible? any help is appreciated. edit: my excuse is that I'm a beginner to Python so, sorry if this question has super obvious errors/mistakes
I fixed it. Here's the code if anyone's stuck on the same question: The first code was provided by Matthias, which was much cleaner, please use it.
def array_diff(a, b):
return [value for value in a if value not in b]
# CREDITS TO MATTHIAS FOR THIS SIMPLE SOLUTION
My code, if anyone's interested:
def array_diff(a, b):
#if a == []: return b
#if b == []: return a
# these if statements are replaced by the"for item in range" code below
for occurrence in b:
if occurrence in a:
for item in range(a.count(occurrence)):
a.remove(occurrence)
return a