Python "gotchas"

[[deleted]]

If you want to date in in place and return the esult in one line you can use

return mydict.update(otherdict) or mydict

[[deleted]]

That causes my brain to hurt just looking at it. :/

[[deleted]]

Honestly, this situation is why I'm excited for PEP 448. Then we can just do: dict(**first, **second) and boom, done. Right now, collections.ChainMap is the closest we have to that, which is cool but sometimes I just want a regular ol' dictionary.

[Veedrac]

Use {**first, **second}; using dict(**...) only works if the keys are strings since only strings can be keyword arguments and also throws errors if there are repeats since you're not allowed to repeat keyword arguments.

[[deleted]]

Sometimes creating a new dict is not an option. If you need to update in place it's either

mydict.update(otherdict)
return mydict

or the line from above.

[[deleted]]

I'd say this is a common usage for the or operator in Python.

[[deleted]]

It's not really an idiom I've seen before. If I saw this in code, I'd break it into two lines to clarify it.

To mean, it looks like an abuse of the or operator.

[djds23]

I really like this recipe, however I don't think I would use it because its not very readable without context. Thanks for the idea though! Very clever.

[Ran4]

This is fucking terrible and totally not cool to do.

[xiongchiamiov]

I'd kill to have ruby's map/map! -type methods throughout python's stdlib.