A method returns iterator object. I want to check the number of data to test.
I think it is a simple question, but I coundn't resolve it.
records = a_function()
self.assertEqual(1, len(records)) # TypeError: object of type 'listiterator' has no len()
Python2.7
You need to convert the iterator to a list first:
len(list(records))
See:
>>> some_list = [1, 2, 3, 4, 5]
>>> it = iter(list)
>>> it = iter(some_list)
>>> len(it)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: object of type 'list_iterator' has no len()
>>> len(list(it))
5
>>>
Note, however, that this will consume the iterator:
>>> list(it)
[]
>>>
records is iterator object, this name is not suitable, I think. Thank you everyone.You can easily do it by
sum(1 for _ in it)
where it is the iterator you want to find length.
