Check if something is (not) in a list in Python

python list conditional membership
Zack picture Zack · May 2, 2012 · Viewed 1.2M times · Source

I have a list of tuples in Python, and I have a conditional where I want to take the branch ONLY if the tuple is not in the list (if it is in the list, then I don't want to take the if branch)

if curr_x -1 > 0 and (curr_x-1 , curr_y) not in myList: 

    # Do Something

This is not really working for me though. What have I done wrong?

Answer

orlp picture orlp · May 2, 2012

The bug is probably somewhere else in your code, because it should work fine:

>>> 3 not in [2, 3, 4]
False
>>> 3 not in [4, 5, 6]
True

Or with tuples:

>>> (2, 3) not in [(2, 3), (5, 6), (9, 1)]
False
>>> (2, 3) not in [(2, 7), (7, 3), "hi"]
True

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