How do I annotate types in a for-loop

I want to annotate a type of a variable in a for-loop.
I tried this:

for

for i: int in range(5):
pass


But it didn't work, obviously.

What I expect is working autocomplete in PyCharm 2016.3.2.
Pre-annotation like this:

i: int
for i in range(5):
pass


doesn't help.

P.S. Pre-annotation works for PyCharm >= 2017.1

4 Answers
4

According to PEP 526, this is not allowed:

In addition, one cannot annotate variables used in a for or with
statement; they can be annotated ahead of time, in a similar manner to
tuple unpacking

for

with

Annotate it before the loop:

i: int
for i in range(5):
pass


PyCharm 2018.1 and up now recognizes the type of the variable inside the loop. This was not supported in older PyCharm versions.

i

I don't know if this solution is PEP compatible or just a feature of PyCharm but I made it work like this

for i in range(5): #type: int
pass


and I'm using Pycharm Community Edition 2016.2.1

This works well for my in PyCharm (using Python 3.6)

for i in range(5):
i: int = i
pass


None of the responses here were useful, except to say that you can't. Even the accepted answer uses syntax from the PEP 526 document, which isn't valid python syntax. If you try to type in

x: int


You'll see it's a syntax error.

Here is a useful workaround:

for __x in range(5):
x = __x # type: int
print(x)


Do your work with x. PyCharm recognizes its type, and autocomplete works.

x

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