Lambda as iterator in Python returns function object on first iteration

Question

I have this code snippet which I can't understand:

>>> l = lambda: -4, 'c', 0

>>> i = iter(l)

>>> i

<tuple_iterator object at 0x00700CD0>

>>> next(i)

<function <lambda> at 0x0070A4F8>

>>> next(i)

'c'

>>> next(i)

0

>>> next(i)

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

StopIteration

>>>

Why is it returning lambda object on first iteration, instead of -4?

Answer 1

In your code l is tuple with 3 elements: A lambda that returns -4, a string ‘c’, and an integer 0.

The reason that it returns lambda object on first iteration and not -4 is because you need to call the lambda by using parentheses like:

next(i)()