Asterisks in Python

Post by zimablue » Fri, Oct 12, 2018, 1:09 PM UTC

zmmmmm wrote: post #10

This is one of those areas where I find Python a little contradictory. About 50% of the time it's "explicit is better than implicit" and "there should be one and only one good way" and then the other half of the time it's "here's this cool feature for doing something you could do a different way that looks like hieroglyphics and nobody understands but you should totally use it because it's awesome!

  def decorator(f):
      def new_f(*args, **kwargs):
          do_something()
          return f(*args, **kwargs)
      return new_f

Post by nickelcitymario » Fri, Oct 12, 2018, 1:18 PM UTC

yxhuvud wrote: post #66

pavlov wrote: post #28

Earlier quoted context omitted.

This is one of the things that gets me about Python. It makes this big noise about being a super-friendly form of executable pseudocode, but then you open any code example and the first thing you see is two asterisks and the mysterious word "kwargs" (a Swedish dessert perhaps?). I wouldn't mind except for all the haughty pretense about Python being a language that doesn't do this sort of thing. Dear Python, get a gri…

Aside: Swedish does have the word 'kvarg', which is a product made out of sour milk. Some people eat it for breakfast but personally I can't stand it.

Post by bspammer » Fri, Oct 12, 2018, 1:25 PM UTC

aequitas wrote: post #73

pavlov wrote: post #28

Earlier quoted context omitted.

This is one of the things that gets me about Python. It makes this big noise about being a super-friendly form of executable pseudocode, but then you open any code example and the first thing you see is two asterisks and the mysterious word "kwargs" (a Swedish dessert perhaps?). I wouldn't mind except for all the haughty pretense about Python being a language that doesn't do this sort of thing. Dear Python, get a gri…

At least the kwargs word is googleable. So it is relatively easy to find documentation. Unlike list comprehensions which are really hard to google until you know the name.

Post by klodolph » Fri, Oct 12, 2018, 1:32 PM UTC

evincarofautumn wrote: post #81

klodolph wrote: post #53

Earlier quoted context omitted.

For me it’s very rare and used where I would write something like concatMap in Haskell. citiesByState = { 'WA': ['Seattle', 'Spokane', 'Olympia'], 'OR': ['Portland', 'Salem'], 'CA': ['San Francisco', 'Los Angeles', 'San Diego'], } cityToState = {city: state for state, cities in citiesByState.items() for city in cities} I would generally avoid multiple levels in a comprehension but there are some very simple two-level…

In Haskell, these direct equivalents aren’t bad at all: cityToState = Map.fromList [ (city, state) | (state, cities) For multiple “nested loops”, I generally prefer do-notation over both list comprehensions and combinators such as concatMap, unless the structure is simple enough that the combinator version is much shorter.

Post by bunderbunder » Fri, Oct 12, 2018, 1:44 PM UTC

Alex3917 wrote: post #48

zmmmmm wrote: post #10

This is one of those areas where I find Python a little contradictory. About 50% of the time it's "explicit is better than implicit" and "there should be one and only one good way" and then the other half of the time it's "here's this cool feature for doing something you could do a different way that looks like hieroglyphics and nobody understands but you should totally use it because it's awesome!

> This is one of those areas where I find Python a little contradictory. It's not contradictory. You should never use args and kwargs unless you need them. Usually they're only needed in relatively rare situations, like A) when you're building a dictionary dynamically without knowing what the key names will be in advance B) when building a library where you want to allow people to subclass a parent class, but also re…