Test for membership should be "not in"

[GuyHoozdis]

A linter would yeild an error on the anti-pattern code. Even though it is anti-pattern code, it should demonstrate best practices for everything except the anti-pattern being demonstrated.

Although not 'k' in d and 'k' not in d ultimately produce the same bytecode, the former is actually two operations and must be optimized to produce identical bytecode to the latter.

The preferred syntax would be 'k' not in d - per the pep8/flake8 linter.

References:

• https://github.com/PyCQA/pycodestyle/blob/1.7.0/pep8.py#L1077-L1078
• http://stackoverflow.com/questions/17659303/what-is-more-pythonic-for-not

[adewes]

great, thanks @GuyHoozdis !

[GuyHoozdis]

The Little Book of Python Anti-Patterns is a wonderful resource. It was my pleasure to read and to make this minor contribution. Hopefully, I will be able to contribute more in the future.

Until then...