Comparing the 1st element of list of lists to another list then adding only the lists that match to-CodePudding

My aim is to compare the 1st element of a list of lists with another list and have the lists added to a new list if the 1st elements of both lists match. So for instance,

list1 = [2,4,7,10]
list2 = [[2,5],[3,7],[1,6],[10,3]]

newlist = [[2,5],[10,3]]

CodePudding user response：

I would use a list comprehension:

[snd for fst, snd in zip(list1, list2) if fst == snd[0]]

This outputs:

[[2, 5], [10, 3]]

CodePudding user response：

You can use zip():

newlist = []

for a, b in zip(list1, list2):
    if a == b[1]:
        newlist.append(b)

Or with a generator expression:

newlist = [b for a, b in zip(list1, list2) if a == b[1]]