Get iterator object from inside the loop

Question

I want to get the iteration object from the loop. I want to avoid storing it in another variable and accessing it. Is there a better way to do it, something like get_current_iterator()?

        for idx, number in enumerate(range(1, 10)):
            # need to refer to enum object for use with
            # next()

No, there isn't. The normal way would be to do something like en = enumerate(range(1, 10)); for i, e in en: ... — juanpa.arrivillaga
– juanpa.arrivillaga, Commented Jun 11, 2019 at 20:11
Possible solution for Python 3.8: for idx, number in (en := enumerate(range(1,10))): — chepner
– chepner, Commented Jun 11, 2019 at 20:12
@Error-SyntacticalRemorse beauty is in the eye of the beholder. The fights around that PEP were pretty much what drove Guido to step down as BDFL — roganjosh
– roganjosh, Commented Jun 11, 2019 at 20:17
You have to be careful, too, since next(en) in the loop could raise a StopIteration that the for loop won't catch for you. — chepner
– chepner, Commented Jun 11, 2019 at 20:20

Andrej Kesely · Accepted Answer · 2019-06-11 20:27:51Z

1

for idx, number, en in iter(lambda en=enumerate(range(1, 10)): (*next(en), en), 0):
    print(en, idx, number)

Prints:

<enumerate object at 0x7f74a11b7a68> 0 1
<enumerate object at 0x7f74a11b7a68> 1 2
<enumerate object at 0x7f74a11b7a68> 2 3
<enumerate object at 0x7f74a11b7a68> 3 4
<enumerate object at 0x7f74a11b7a68> 4 5
<enumerate object at 0x7f74a11b7a68> 5 6
<enumerate object at 0x7f74a11b7a68> 6 7
<enumerate object at 0x7f74a11b7a68> 7 8
<enumerate object at 0x7f74a11b7a68> 8 9

answered Jun 11, 2019 at 20:27

Andrej Kesely

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1 Comment

juanpa.arrivillaga Over a year ago

this also simply stores it in a variable to access it. This is just a very convoluted way of doing en = enumerate(range(1, 10)) before the loop.

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