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0 pointskbenson11y ago0 comments

Python's list comprehensions always struck me as an odd way to go given Python's tendency to choose clarity and simplicity over complexity and expressiveness. As a Perl user, Python list comprehensions make me go cross-eyed half the time. It's something Perl specifically decided to forego as too complex and prone to causing confusion, which is saying something.

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mpdehaan211y ago· 1 in thread

Nesting them I feel is almost always bad

blarg = [ foo(x) for x in y if x > 2]

I think is pretty decent. Helps if they are calling named functions, so it's more self documenting, depending on complexity.

Dict comprehensions can be a little brain-warping too :)

kbensonOP11y ago

Yeah, the Perl equivalent of that is:

  my @blarg = map { foo($_) } grep { $_ > 2 } @y;

A bit more verbose, but if you know Perl, obvious (and the same building blocks allow for more powerful constructs[1], since they really are functional code blocks).

You can argue the Python version is clearer, but placement of the conditional always throws me off. I like to think of my transforms as a pipeline.

1: http://en.wikipedia.org/wiki/Schwartzian_transform

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