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Re: "short circuiting" And and Or

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  • Subject: [mg70610] Re: [mg70582] "short circuiting" And and Or
  • From: Carl Woll <carlw at>
  • Date: Sat, 21 Oct 2006 05:13:52 -0400 (EDT)
  • References: <>

Szabolcs Horvat wrote:

>I'd like to write a function that tests whether there are any elements
>in a list that violate a certain condition. I could simply use
>And@@condition/@list, but for reasons of efficiency I'd like to stop
>the testing as soon as a "False" value is found. Is there any elegant
>way of doing this without writing an explicit While loop?
>Szabolcs Horvát
In addition to using ReleaseHold/Hold, another idea is possible if 
And[list] doesn't evaluate. For example:

condition[x_]:=(Print[x]; Positive[x])

condition /@ And @@ {1,1,-1,1,1,-1,1}

Carl Woll
Wolfram Research

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