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pythonlistextractnested-listssublist

Extract first item of each sublist in Python


I'm wondering what is the best way to extract the first item of each sublist in a list of lists and append it to a new list. So if I have:

lst = [[a,b,c], [1,2,3], [x,y,z]]

And, I want to pull out a, 1 and x and create a separate list from those.

I tried:

lst2.append(x[0] for x in lst)

Solution

  • Using list comprehension:

    >>> lst = [['a','b','c'], [1,2,3], ['x','y','z']]
    >>> lst2 = [item[0] for item in lst]
    >>> lst2
    ['a', 1, 'x']