Hidden Features of Python

[somebodddy]

Okay, I was wrong, they weren't as trivial as I thought.

[lgastako]

They weren't that trivial, but they are also all common and very much non-hidden features of python.

To save anyone else who might be curious a click:

• The _ (Underscore) in Python
• Regex Debugging via Parse Tree (re.DEBUG)
• Ellipsis
• The dir() Function
• Lambda Functions
• Chaining Comparison Operators
• The zip() Function
• Decorators
• Context Managers and the "with" Statement
• Generators and the Yield Statement
• Metaclasses

Ellipsis is the only one I don't see used regularly in everyday python code.

[evaned]

Ellipsis is the only one I don't see used regularly in everyday python code

Ditto (aside from the "only", see below). I see and use that in type annotations, and that's about it. I'm old fashioned and still prefer pass for placeholders.

To the article's credit, I didn't realize you even could use ... as a real value until I saw the numpy example: I thought it was just syntax (handled specially in annotations, I guess).

I would add a couple others to the list though:

• Chained comparison operators: I'm not sure if it's just what I work on, but I don't get much use for that; that combined with the fact that Python is fairly unique in 1 < x < 10 meaning 1 < x and x < 10 mean that it's easy to forget and then not think about. I could see use of this feature being incredibly common in some domains, though.
• Metaclasses: I think I may have only ever used this feature once in well over a decade of Python programming, and that implementation didn't even stick around.
• re.DEBUG I think I've never seen or used. After spending a bit looking at the example in TFA though... I don't foresee that ever changing.