pythonfor-looppycharmpython-typing

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 but it didn't work:

for i: int in range(5):
    pass

What I expect is working autocomplete in PyCharm 2016.3.2, but using pre-annotation didn't work:

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

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

Solution

  • 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

    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.