PyCharm - 尾随类型提示和行宽限制

Question

In PyCharm, I typically use trailing type hints (not sure of the right way of calling them) for variables such as this:

my_var = my_other_variable  # type: MyObject

However, sometimes I already have a very long line which I cannot really split, or the type hint is a bit long, such as:

my_var = my_really_long_variable_name  # type: QtWidgets.QVeryLongQtClassName

This would make the full line longer than my line width limit (79 characters), and hence PyCharm would flag a warning.

Hence, is there a way to put the type hint in a different line? I tried these but they do not seem to work:

# type: QtWidgets.QVeryLongQtClassName
my_var = my_really_long_variable_name

my_var = my_really_long_variable_name \
    # type: QtWidgets.QVeryLongQtClassName

The closest thing I can think of is this, which may not really shorten that much the line width:

my_var = \
    my_really_long_variable_name  # type: QtWidgets.QVeryLongQtClassName

Otherwise, the only alternative I have is to do something like this:

v = my_really_long_variable_name
my_var = v  # type: QtWidgets.QVeryLongQtClassName

The other alternative of shortening the type does not seem to work based on the tests I have done; PyCharm seems to struggle recognising that my_var 's type is really QtWidgets.QVeryLongQtClassName in this case:

t = QtWidgets.QVeryLongQtClassName
my_var = my_really_long_variable_name  # type: t

Answer 1

I found it very convenient to import the class names directly from the module for the type annotation usage. For example:

from QtWidgets import QVeryLongQtClassName
my_var = my_really_long_variable_name  # type: QVeryLongQtClassName

I have not encountered a problem like yours yet with this attitude.

However, I found this version to be the most readable and convenient way to annotate a long line:

my_var = \
    my_really_long_variable_name  # type: QtWidgets.QVeryLongQtClassName

UPDATE: Another way to implement this:

my_var = (
    my_really_long_variable_name
)  # type: QtWidgets.QVeryLongQtClassName

In addition, it is supported and does not cause problems in most IDEs.