Test type of elements python tuple/list


How do you verify that the type of all elements in a list or a tuple are the same and of a certain type?

for example:

(1, 2, 3)  # test for all int = True
(1, 3, 'a') # test for all int = False
Asked By: 9-bits



all(isinstance(n, int) for n in lst)


In [3]: lst = (1,2,3)

In [4]: all(isinstance(n, int) for n in lst)
Out[4]: True

In [5]: lst = (1,2,'3')

In [6]: all(isinstance(n, int) for n in lst)
Out[6]: False

Instead of isinstance(n, int) you could also use type(n) is int

Answered By: ThiefMaster
all(isinstance(i, int) for i in your_list))
Answered By: pod2metra

Depending on what you’re doing it may be more Pythonic to use duck typing. That way, things that are int-like (floats, etc.) can be passed as well as ints. In this case, you might try converting each item in the tuple to an int, and then catch any exceptions that arise:

>>> def convert_tuple(t, default=(0, 1, 2)):
...     try:
...         return tuple(int(x) for x in t)
...     except ValueError, TypeError:
...         return default

Then you can use it like so:

>>> convert_tuple((1.1, 2.2, 3.3))
(1, 2, 3)
>>> convert_tuple((1.1, 2.2, 'f'))
(0, 1, 2)
>>> convert_tuple((1.1, 2.2, 'f'), default=(8, 9, 10))
(8, 9, 10)
Answered By: senderle

Only to mention the possibility, you can avoid list comprehension with:

all(map(lambda x: isinstance(x, int), your_list))
Answered By: Mario Wanka

you can also check type of elements using ‘type’ function in python like-

>>> all(type(n) == int for n in last) # [1, 2, 2, 34]
>>> all(type(n) == str for n in last) # [1, 2, 2, 34]
Answered By: Mayank Maheshwari
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