how to find complement in two lists

April 10, 2022

There are two phones, phoneA and phoneB, how to how to find complement in phoneB but not in phoneA, one ex;

phoneA =  ["long lasting battery”, ”clear display”, ”great camera”, ”storage space”], [“clear display”, ”long lasting battery”, ”great camera”, ”warp-speed word processing”]

phoneB =  ["long lasting battery”, ”clear display”, ”great camera”, ”storage space”], [“clear display”, ”long lasting battery”, ”great camera”, ”warp-speed word processing”, “great sound”]

I write code like this by python:

d = [x for x in phoneB if x not in phoneA]
print(d)

but the code is wrong, anyone has better idea?

>Solution :

You need to add the 2 lists together, then check them:

d = [x for x in phoneB[0]+phoneB[1] if x not in phoneA[0]+phoneA[1]]

>>> d
['great sound']

Or if you have multiple sublists, this will also work:

# This joins all the elements in sublists into one large list
d = [x for x in [j for i in phoneB for j in i]
     if x not in [j for i in phoneA for j in i]]