johnfk3 - 29 days ago 5x
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:
templist.append(i[0])

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
`j[0]`

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:
result.append(items[0]+(0,0))
else:
result.append(items[0]+items[1][1:])
print(result)
``````

Output:

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