How to concatenate tuples

Question

I have this code:

def make_service(service_data, service_code):
    routes = ()
    curr_route = ()
    direct = ()

    first = service_data[0]
    curr_dir = str(first[1])

    for entry in service_data:
        direction = str(entry[1])
        stop = entry[3]

        if direction == curr_dir:
            curr_route = curr_route + (stop, )
            print((curr_route))

When I print((curr_route)), it gives me this result:

('43009',)
('43189', '43619')
('42319', '28109')
('42319', '28109', '28189')
('03239', '03211')
('E0599', '03531')

How do I make it one tuple? i.e. ('43009','43189', '43619', '42319', '28109', '42319', '28109', '28189', '03239', '03211', 'E0599', '03531')

The following sample works for me , Is it posssible you changed `curr_route` before `if` section? — ᴀʀᴍᴀɴ, Feb 21 '16 at 09:01
I cant underestand it in comment , please add it into question! — ᴀʀᴍᴀɴ, Feb 21 '16 at 09:06
Python 3.5.1 I don't think the rest of the code matters, I think it's really just because of how the data is arranged and I'm trying to work around that. — drowningincode, Feb 21 '16 at 09:24
sorry, but `print((curr_route))` *cannot* give the result you list. Please prepare a [MVCE](http://stackoverflow.com/help/mcve) of your issue and show us in the question. — flaschbier, Feb 21 '16 at 09:31

score 2 · Answer 1 · answered Feb 04 '17 at 22:37

2

tuples = (('hello',), ('these', 'are'), ('my', 'tuples!'))
sum(tuples, ())

gives ('hello', 'these', 'are', 'my', 'tuples!') in my version of Python (2.7.12). Truth is, I found your question while trying to find how this works, but hopefully it's useful to you!

answered Feb 04 '17 at 22:37

Willbeing

121
3

if you wonder about the performance of this answer, go (here)[https://stackoverflow.com/questions/42059646/concatenate-tuples-using-sum]. Basically, it is OK for small tuples, but went there is a lot of tuples you would prefer to use itertools: `import itertools as it: tuple(it.chain.from_iterable(tuples))` – toto_tico Aug 31 '17 at 14:16
Also notice that if you want to iterate over the values, itertool returns an iterator and this could really make the difference as you won't have to iterate the elements twice: `for i in it.chain.from_iterable(tuples): print(i)` – toto_tico Aug 31 '17 at 14:18

JulienD · Answer 2 · 2016-02-21T09:53:30.867

Tuples exist to be immutable. If you want to append elements in a loop, create an empty list curr_route = [], append to it, and convert once the list is filled:

def make_service(service_data, service_code):
    curr_route = []
    first = service_data[0]
    curr_dir = str(first[1])

    for entry in service_data:
        direction = str(entry[1])
        stop = entry[3]

        if direction == curr_dir:
            curr_route.append(stop)

    # If you really want a tuple, convert afterwards:
    curr_route = tuple(curr_route)
    print(curr_route)

Notice that the print is outside of the for loop, which may be simply what you were asking for since it prints a single long tuple.

How to concatenate tuples

2 Answers2

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