Re: Retrieve and In Bug?

[Aharon Robbins]

Greetings.   This is not a bug.  It is the way the awk
language is defined to work.  The gawk doc thus describes
that `foo in a' is the right way to test for the existence
of a subscript, since `a[foo] != ""' has the side effect
of creating a[foo].

Thanks,

Arnold

> Date: Mon, 19 Jul 2004 11:26:28 +0200
> From: "Gerrit Riessen" <address@hidden>
> To: address@hidden
> Subject: Retrieve and In Bug?
> Organization: http://freemail.web.de/
>
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>
> Hello,
>
> I might have found a bug in the handling values that are not
> defined in arrays.
>
> Basically what I do is attempt to retrieve a value that is not
> defined as an index in an array, i.e. value = array[index]. This causes
> if the index is not defined, i.e. (index in array) returns 0, to define
> the index, i.e. (index in array) returns 1 after calling value = array[index].
>
> I've tested this on GNU/Linux with Gawk 3.1.0 and on Win2000 with
> Gawk 3.1.3. I've also included the test program.
>
> Cheers, Gerrit
>
>
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>
> # -*- awk -*-
> # test.gawk
> #
> # Author: Gerrit Riessen, address@hidden 
> # Copyright (C) 2004 Gerrit Riessen
> # This code is licensed under the GNU Public License.
> # $Id$ 
> #
> BEGIN {
>   a[1] = 1;
>   a[2] = 2;
>   print "Is 3 in a?: " (3 in a);
>   for ( idx in a ) print idx " = " a[idx];
>   v = a[3];
>   print "Is 3 in a?: "(3 in a);
>   for ( idx in a ) print idx " = " a[idx];
>   exit;
> }
>
> #### Returns on Linux: (GNU Awk 3.1.0)
> # Is 3 in a?: 0
> # 1 = 1
> # 2 = 2
> # Is 3 in a?: 1
> # 1 = 1
> # 2 = 2
> # 3 = 
>
> #### Returns on Win2000: (GNU Awk 3.1.3)
> # Is 3 in a?: 0
> # 1 = 1
> # 2 = 2
> # Is 3 in a?: 1
> # 1 = 1
> # 2 = 2
> # 3 = 
>
>
> --STEFAN40fb93c55672--