Convert list to tuple in Python

The Question :

574 people think this question is useful

I’m trying to convert a list to a tuple.

Most solutions on Google offer the following code:

l = [4,5,6]
tuple(l)

However, the code results in an error message when I run it:

TypeError: ‘tuple’ object is not callable

How can I fix this problem?

The Question Comments :
  • Did you assign the variable name tuple elsewhere before?
  • Not to be overly picky, but you probably also shouldn’t use lower case “el” as a variable name due to its resemblance to 1. Same goes for capital “oh” due to its resemblance to zero. Even “li” is much more readable in comparison.

The Answer 1

861 people think this answer is useful

It should work fine. Don’t use tuple, list or other special names as a variable name. It’s probably what’s causing your problem.

>>> l = [4,5,6]
>>> tuple(l)
(4, 5, 6)

The Answer 2

113 people think this answer is useful

Expanding on eumiro’s comment, normally tuple(l) will convert a list l into a tuple:

In [1]: l = [4,5,6]

In [2]: tuple
Out[2]: <type 'tuple'>

In [3]: tuple(l)
Out[3]: (4, 5, 6)

However, if you’ve redefined tuple to be a tuple rather than the type tuple:

In [4]: tuple = tuple(l)

In [5]: tuple
Out[5]: (4, 5, 6)

then you get a TypeError since the tuple itself is not callable:

In [6]: tuple(l)
TypeError: 'tuple' object is not callable

You can recover the original definition for tuple by quitting and restarting your interpreter, or (thanks to @glglgl):

In [6]: del tuple

In [7]: tuple
Out[7]: <type 'tuple'>

The Answer 3

30 people think this answer is useful

You might have done something like this:

>>> tuple = 45, 34  # You used `tuple` as a variable here
>>> tuple
(45, 34)
>>> l = [4, 5, 6]
>>> tuple(l)   # Will try to invoke the variable `tuple` rather than tuple type.

Traceback (most recent call last):
  File "<pyshell#10>", line 1, in <module>
    tuple(l)
TypeError: 'tuple' object is not callable
>>>
>>> del tuple  # You can delete the object tuple created earlier to make it work
>>> tuple(l)
(4, 5, 6)

Here’s the problem… Since you have used a tuple variable to hold a tuple (45, 34) earlier… So, now tuple is an object of type tuple now…

It is no more a type and hence, it is no more Callable.

Never use any built-in types as your variable name… You do have any other name to use. Use any arbitrary name for your variable instead…

The Answer 4

27 people think this answer is useful

To add another alternative to tuple(l), as of Python >= 3.5 you can do:

t = *l,  # or t = (*l,) 

short, a bit faster but probably suffers from readability.

This essentially unpacks the list l inside a tuple literal which is created due to the presence of the single comma ,.


P.s: The error you are receiving is due to masking of the name tuple i.e you assigned to the name tuple somewhere e.g tuple = (1, 2, 3).

Using del tuple you should be good to go.

The Answer 5

3 people think this answer is useful

I find many answers up to date and properly answered but will add something new to stack of answers.

In python there are infinite ways to do this, here are some instances
Normal way

>>> l= [1,2,"stackoverflow","python"]
>>> l
[1, 2, 'stackoverflow', 'python']
>>> tup = tuple(l)
>>> type(tup)
<type 'tuple'>
>>> tup
(1, 2, 'stackoverflow', 'python')

smart way

>>>tuple(item for item in l)
(1, 2, 'stackoverflow', 'python')

Remember tuple is immutable ,used for storing something valuable. For example password,key or hashes are stored in tuples or dictionaries. If knife is needed why to use sword to cut apples. Use it wisely, it will also make your program efficient.

The Answer 6

-1 people think this answer is useful

l1=[]#empty list is given

l1=tuple(l1)#through the type casting method we can convert list into tuple

print(type(l1))#now this show class of tuple

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