append tuples to a list

Question

How can I append the content of each of the following tuples (ie, elements within the list) to another list which already has 'something' in it? So, I want to append the following to a list (eg: result[]) which isn't empty:

l = [('AAAA', 1.11), ('BBB', 2.22), ('CCCC', 3.33)]

Obviously, the following doesn't do the thing:

for item in l:
    result.append(item)
    print result

I want to printout:

[something, 'AAAA', 1.11] 
[something, 'BBB', 2.22] 
[something, 'CCCC', 3.33]

Do you want _all_ the tuples to be appended to the list, one after another? Or only one at a time? In other words, are you looking for one list containing `[something, tuple1, tuple2, tuple3]`, or several lists, `[something, tuple1]`, `[something, tuple2]`, and `[something, tuple3]`? — David Z, Jul 18 '10 at 03:50
The title is misleading, since based just on the title the answer would be `result.extend(item)` instead. — user2340939, Jan 11 '22 at 12:37

score 44 · Accepted Answer · answered Jul 18 '10 at 02:33

44

result.extend(item)

answered Jul 18 '10 at 02:33

Ignacio Vazquez-Abrams

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Nifty, didn't know `extend` would just handle the tuple the right way. – John Jul 18 '10 at 02:46
2

@John: `list.extend()` takes any iterable. – Ignacio Vazquez-Abrams Jul 18 '10 at 02:49
would `result += item` work, as per [this question](http://stackoverflow.com/questions/3653298/concatenating-two-lists-difference-between-and-extend) ? – J0ANMM Oct 14 '16 at 13:44

score 5 · Answer 2 · answered Jul 18 '10 at 02:38

5

You can convert a tuple to a list easily:

>>> t = ('AAA', 1.11)
>>> list(t)
['AAAA', 1.11]

And then you can concatenate lists with extend:

>>> t = ('AAA', 1.11)
>>> result = ['something']
>>> result.extend(list(t))
['something', 'AAA', 1.11])

answered Jul 18 '10 at 02:38

John

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cletus · Answer 3 · 2010-07-18T02:55:40.640

3

You can use the inbuilt list() function to convert a tuple to a list. So an easier version is:

l = [('AAAA', 1.11), ('BBB', 2.22), ('CCCC', 3.33)]
result = [list(t) for t in l]
print result

Output:

[['AAAA', 1.1100000000000001],
 ['BBB', 2.2200000000000002],
 ['CCCC', 3.3300000000000001]]

edited Jul 18 '10 at 02:55

answered Jul 18 '10 at 02:34

cletus

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why do I get: TypeError: 'tuple' object is not callable? – DGT Jul 18 '10 at 02:43
@DGT no idea. what version of python are you using? The above is fine in 2.6/2.7. – cletus Jul 18 '10 at 02:56
1

@DGT: You're probably omitting a comma following a tuple. Something like (a, b, c) (d, e, f) will produce that error. The fixed version would be (a, b, c), (d, e, f) – Dan Breslau Jul 18 '10 at 03:39

Kit · Answer 4 · 2010-07-18T02:42:02.093

1

You will need to unpack the tuple to append its individual elements. Like this:

l = [('AAAA', 1.11), ('BBB', 2.22), ('CCCC', 3.33)]

for each_tuple in l:
  result = ['something']
  for each_item in each_tuple:
    result.append(each_item)
    print result

You will get this:

['something', 'AAAA', 1.1100000000000001]
['something', 'BBB', 2.2200000000000002]
['something', 'CCCC', 3.3300000000000001]

You will need to do some processing on the numerical values so that they display correctly, but that would be another question.

edited Jul 18 '10 at 02:42

answered Jul 18 '10 at 02:35

Kit

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No, not this. But this is the only guy who at least managed to read the question till the end. – Slava Jan 02 '17 at 16:47

append tuples to a list

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