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Re: Supply condition in function call

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On Wed, Mar 25, 2015 at 11:29 AM, Manuel Graune <manuel.graune@koeln.de> wrote:
> Hi,
>
> I'm looking for a way to supply a condition to an if-statement inside a
> function body when calling the function. I can sort of get what I want
> with using eval (see code below) but I would like to achieve this in a
> safer way. If there is a solution which is safer while being
> less flexible, that would be fine. Also, supplying the condition as a
> string is not necessary. What I want to do is basically like this:
>
> def test1(a, b, condition="True"):
>     for i,j in zip(a,b):
>         c=i+j
>         if eval(condition):
>            print("Foo")

Pass the condition as a function.

def test1(a, b, condition=lambda i, j: True):
    for i,j in zip(a,b):
        c=i+j
        if condition(i, j):
            print("Foo")

test1([0,1,2,3],[1,2,3,4], lambda i, j: i+j > 4)
# etc.

If you find lambdas confusing and prefer named functions, those will
work just as well.

def i_plus_j_gt_4(i, j):
    return i + j > 4

test1([0,1,2,3],[1,2,3,4], i_plus_j_gt_4)

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Supply condition in function call Manuel Graune <manuel.graune@koeln.de> - 2015-03-25 18:29 +0100
  Re: Supply condition in function call Joel Goldstick <joel.goldstick@gmail.com> - 2015-03-25 13:41 -0400
    Re: Supply condition in function call Manuel Graune <manuel.graune@koeln.de> - 2015-03-25 18:51 +0100
      Re: Supply condition in function call Joel Goldstick <joel.goldstick@gmail.com> - 2015-03-25 14:17 -0400
      Re: Supply condition in function call Ian Kelly <ian.g.kelly@gmail.com> - 2015-03-25 12:22 -0600
      Re: Supply condition in function call Joel Goldstick <joel.goldstick@gmail.com> - 2015-03-25 14:42 -0400
  Re: Supply condition in function call Ian Kelly <ian.g.kelly@gmail.com> - 2015-03-25 11:44 -0600
    Re: Supply condition in function call Grant Edwards <invalid@invalid.invalid> - 2015-03-25 19:53 +0000
      Re: Supply condition in function call Ian Kelly <ian.g.kelly@gmail.com> - 2015-03-25 14:49 -0600
        Re: Supply condition in function call Grant Edwards <invalid@invalid.invalid> - 2015-03-26 15:41 +0000
  Re: Supply condition in function call Terry Reedy <tjreedy@udel.edu> - 2015-03-25 14:50 -0400
  Re: Supply condition in function call Gary Herron <gherron@digipen.edu> - 2015-03-25 12:13 -0700
    Re: Supply condition in function call Rustom Mody <rustompmody@gmail.com> - 2015-03-25 21:02 -0700
      Re: Supply condition in function call Chris Angelico <rosuav@gmail.com> - 2015-03-26 17:00 +1100
        Re: Supply condition in function call Rustom Mody <rustompmody@gmail.com> - 2015-03-26 18:41 -0700
          Re: Supply condition in function call Chris Angelico <rosuav@gmail.com> - 2015-03-27 12:56 +1100
            Re: Supply condition in function call Rustom Mody <rustompmody@gmail.com> - 2015-03-26 19:21 -0700
              Re: Supply condition in function call Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-03-27 15:34 +1100
                Re: Supply condition in function call Rustom Mody <rustompmody@gmail.com> - 2015-03-27 06:48 -0700
                Re: Supply condition in function call Chris Angelico <rosuav@gmail.com> - 2015-03-28 01:17 +1100
                Re: Supply condition in function call Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-03-27 16:00 +0000
                Re: Supply condition in function call Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-03-28 18:32 +1100
                Re: Supply condition in function call Chris Angelico <rosuav@gmail.com> - 2015-03-28 18:45 +1100
            Re: Supply condition in function call Larry Hudson <orgnut@yahoo.com> - 2015-03-27 17:26 -0700
              Re: Supply condition in function call Rustom Mody <rustompmody@gmail.com> - 2015-03-27 18:27 -0700
              Re: Supply condition in function call Marko Rauhamaa <marko@pacujo.net> - 2015-03-28 09:50 +0200
                Re: Supply condition in function call Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-03-28 20:17 +1100
                Re: Supply condition in function call Ian Kelly <ian.g.kelly@gmail.com> - 2015-03-28 03:19 -0600
                Re: Supply condition in function call Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-03-28 20:57 +1100
                Re: Supply condition in function call Cameron Simpson <cs@zip.com.au> - 2015-03-30 09:35 +1100
                Re: Supply condition in function call Manuel Graune <manuel.graune@koeln.de> - 2015-03-30 00:46 +0200
          Re: Supply condition in function call Ian Kelly <ian.g.kelly@gmail.com> - 2015-03-26 20:25 -0600
            Re: Supply condition in function call Rustom Mody <rustompmody@gmail.com> - 2015-03-26 19:46 -0700
    Re: Supply condition in function call Manuel Graune <manuel.graune@koeln.de> - 2015-03-26 07:27 +0100
      Re: Supply condition in function call Cameron Simpson <cs@zip.com.au> - 2015-03-26 18:06 +1100
        Re: Supply condition in function call Manuel Graune <manuel.graune@koeln.de> - 2015-03-27 21:02 +0100
          Re: Supply condition in function call Cameron Simpson <cs@zip.com.au> - 2015-03-28 09:55 +1100
      Re: Supply condition in function call Peter Otten <__peter__@web.de> - 2015-03-26 10:03 +0100
        Re: Supply condition in function call Manuel Graune <manuel.graune@koeln.de> - 2015-03-27 20:46 +0100
          Re: Supply condition in function call Peter Otten <__peter__@web.de> - 2015-03-27 21:38 +0100
  Re: Supply condition in function call smap <askme.first@thankyouverymuch.invalid> - 2015-03-28 08:58 +0000

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