how to find complement in two lists

Question

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?

Answer 1

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']

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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]]