CODEWITHSUNDEEP
pythonlistappend
alexjones
alexjones

Reputation: 86

Appending a List with Some Values of Another List

I have a list of lists mainList. I wish to append this list with a subList , but only the 2nd, 3rd, 4th, 5th, and 7th items. 

for subList in file:
    mainList.append(subList[#items 2,3,4,5,7])

Is there a way to do this besides

for subList in file:
    temp = []
    for item in subList[1:]:
        if #item not the 6th item:
            temp.append(item)
    mainList.append(temp)

Can I do this without the temp list and the nested for loop appending this list?

Upvotes: 2

Views: 69

Answers (3)

wim
wim

Reputation: 362478

I would do it like this, simple and Pythonic with a list comprehension:

indices = 2,3,4,5,7
mainList.append([sublist[i] for i in indices])

Upvotes: 5

Błotosmętek
Błotosmętek

Reputation: 12927

This should do:

mainList.extend(subList[1:6])
mainList.append(subList[7])

Upvotes: 0

Moses Koledoye
Moses Koledoye

Reputation: 78536

You can use operator.itemegetter to fetch the items from subList, returning a tuple. You can afterwards cast to a list before appending:

from operator import itemgetter

f = itemgetter(2,3,4,5,7)

for subList in file:
    mainList.append(list(f(subList)))

You may drop the list call if your sublist could also pass as tuples.

Upvotes: 3

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