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Re: Having both if() and for() statements in one liner

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On 2013-09-17 16:21, Ferrous Cranus wrote:
> I just want to say tot he program that
> 
> that only run the for statement if and only if person=='George'
> 
> I dont see nay reason as to why this fails
> 
> perhaps like:
> 
> for times in range(0, 5) if person=='George':
> 
> but that fails too...
> there must be written on soem way.

The canonical way to do this is the obvious:

  if person == "George":
    for times in range(0, 5):
      ...

That said, you can do stupid things to abstract the logic like

  def iterate_if(condition, iterable):
    if condition:
      for item in iterable:
        yield item

which you can use something like

  for times in iterate_if(person == "George", range(0,5)):
    ...

but I don't advise it.  Mainly, because the iterable will be
evaluated when passed as an argument, which incurs the runtime cost.
In the canonical form, if the test isn't passed, the range(n,m) is
never even evaluated.

-tkc

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Having both if() and for() statements in one liner Ferrous Cranus <nikos.gr33k@gmail.com> - 2013-09-17 15:02 +0300
  Re: Having both if() and for() statements in one liner Robert Kern <robert.kern@gmail.com> - 2013-09-17 13:52 +0100
  Re: Having both if() and for() statements in one liner Roy Smith <roy@panix.com> - 2013-09-17 09:00 -0400
    Re: Having both if() and for() statements in one liner Ferrous Cranus <nikos.gr33k@gmail.com> - 2013-09-17 16:21 +0300
      Re: Having both if() and for() statements in one liner Heiko Wundram <modelnine@modelnine.org> - 2013-09-17 15:46 +0200
      Re: Having both if() and for() statements in one liner Tim Chase <python.list@tim.thechases.com> - 2013-09-17 09:17 -0500
      Re: Having both if() and for() statements in one liner Joel Goldstick <joel.goldstick@gmail.com> - 2013-09-17 10:32 -0400
      Re: Having both if() and for() statements in one liner Dave Angel <davea@davea.name> - 2013-09-17 18:54 +0000
        Re: Having both if() and for() statements in one liner Steven D'Aprano <steve@pearwood.info> - 2013-09-18 02:10 +0000
          Re: Having both if() and for() statements in one liner Joshua Landau <joshua@landau.ws> - 2013-09-18 06:55 +0100
          Re: Having both if() and for() statements in one liner Chris Angelico <rosuav@gmail.com> - 2013-09-18 17:00 +1000
    Re: Having both if() and for() statements in one liner Chris Angelico <rosuav@gmail.com> - 2013-09-18 01:04 +1000
    Re: Having both if() and for() statements in one liner Joel Goldstick <joel.goldstick@gmail.com> - 2013-09-17 11:15 -0400

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