How to get first element in a list of tuples?

I have a list like below where the first element is the id and the other is a string:

[(1, u'abc'), (2, u'def')]

I want to create a list of ids only from this list of tuples as below:

[1,2]

I’ll use this list in __in so it needs to be a list of integer values.

Answer

>>> a = [(1, u'abc'), (2, u'def')]
>>> [i[0] for i in a]
[1, 2]