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Re: Boolean function on variable-length lists

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Libra writes:

> Hello,
> 
> I need to implement a function that returns 1 only if all the values
> in a list satisfy given constraints (at least one constraint for
> each element in the list), and zero otherwise.
> 
> For example, I may have a list L = [1, 2, 3, 4] and the following
> constraints:
> L[0] >= 1
> L[1] <= 3
> L[2] == 2
> L[3] >= 3
> 
> In this case, the function returns 0 because the third constraint is
> not satisfied.

So you would associate each constraint with an index. You could
maintain a list of constraints and apply it to the values as follows:

>>> cs = [ lambda x : x >= 1, lambda x : x <= 3, lambda x : x == 2,
...        lambda x : x >= 3 ]
>>> { f(x) for f, x in zip(cs, [1,2,3,4]) }
{False, True}
>>> { f(x) for f, x in zip(cs, [1,2,2,4]) }
{True}
>>> 

Then map the return value to 0 if it contains a False, else to 1.

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Boolean function on variable-length lists Libra <librarama@gmail.com> - 2012-09-12 05:48 -0700
  Re: Boolean function on variable-length lists Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2012-09-12 16:02 +0300
    Re: Boolean function on variable-length lists Tim Chase <python.list@tim.thechases.com> - 2012-09-12 08:18 -0500
    Re: Boolean function on variable-length lists Libra <librarama@gmail.com> - 2012-09-12 06:19 -0700
      Re: Boolean function on variable-length lists Libra <librarama@gmail.com> - 2012-09-12 06:33 -0700
      Re: Boolean function on variable-length lists Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2012-09-12 16:37 +0300
        Re: Boolean function on variable-length lists Ken Seehart <ken@seehart.com> - 2012-09-12 06:51 -0700
        Re: Boolean function on variable-length lists Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-09-12 15:29 +0100
        Re: Boolean function on variable-length lists MRAB <python@mrabarnett.plus.com> - 2012-09-12 16:55 +0100
  Re: Boolean function on variable-length lists Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-09-12 13:11 +0000
    Re: Boolean function on variable-length lists Libra <librarama@gmail.com> - 2012-09-12 06:25 -0700

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