johnfk3 johnfk3 - 1 year ago 61
Python Question

Concatanate tuples in list of tuples

I have a list of tuples that looks something like this:

tuples = [('a', 10, 11), ('b', 13, 14), ('a', 1, 2)]

Is there a way that i can join them together based on the first index of every tuple to make a each tuple contain 5 elements. I know for a fact there isn't more that 2 of each letter in the tuples, Ie more than 2 'a's or 'b's in the entire list. The other requirement is to use Python2.6. I cant figure out the logic to it. Any help is greatly appreciated.

Desired Output:

tuples = [('a', 10, 11, 1, 2), ('b', 13, 14, 0, 0)]

I have tried creating a new list of first elements and adding the other elements to it but then I only have a list and not list of tuples.

EDIT to provide previous tried code,

Created a new list:
templist, resultList = [], []

Populate templist with the first element in every tuple:

for i in tuples:

elemlist = list(set(templist))

for i in elemlist:
for j in tuples:
if i == j[0]:
resultlist.append((i, j[1], j[2]))

This just returns the same list of tuples, How can i hold onto it and append every
j[1] j[2]
that corresponds to correct

Answer Source

Assuming there are only one or two of every letter in the list as stated:

import itertools

tuples = [('a', 10, 11), ('b', 13, 14), ('a', 1, 2)]

result = []
key = lambda t: t[0]
for letter,items in itertools.groupby(sorted(tuples,key=key),key):
    items = list(items)
    if len(items) == 1:


[('a', 10, 11, 1, 2), ('b', 13, 14, 0, 0)]
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