The Zen of Python (by example)

Re:The Zen of Python (by example) by ramanujan on Tuesday March 13, 2012 @09:07AM (#3698202)

The "identify this animal" example has a serious bug. This:

  def identify(animal):
      if animal.is_vertebrate():
          return identify_vertebrate()
      else:
          return identify_invertebrate()

should be

  def identify(animal):
      if animal.is_vertebrate():
          return identify_vertebrate(animal)
      else:
          return identify_invertebrate(animal)

Arguably this mix of OO and procedural code is bad as well. But less arguably, the initial example (with a simple identify function) was far better than the rewrite.

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Re:The Zen of Python (by example) by oinksoft on Tuesday March 13, 2012 @09:50AM (#3698384)

In any case the else: is pointless.

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Re:The Zen of Python (by example) by dustingetz on Tuesday March 13, 2012 @03:03PM (#3699841)

its subjective, arguably a style using ternary operator is better because it is composable - it evaluates as an expression, as opposed to a series of statements. it's something the lisp and functional programming people like - no implied dependency on order in which statements execute.

i dunno if this is valid python but it demonstrates the idea

  doSomething(
    identify_vertebrate(animal) if animal.is_vertebrate() \
    else identify_invertebrate(animal))

  doSomething( if( is_vertebrate(animal)
                   identify_vertebrate(animal)
                   identify_invertebrate(animal)))

  (doSomething (if (is_vertebrate animal)
                   (identify_vertebrate animal)
                   (identify_invertebrate animal)))

this is part of "referential transparency", and once you get past "OMG parens" you realize its a Good Thing. parens are caused by a style preferring composition of expressions over executing statements, not lisp.

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Re:The Zen of Python (by example) by bryanh on Tuesday March 13, 2012 @01:49PM (#3699526)

I dunno, I like the readability of an explicit else.

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