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Posted by Ben Bullock on March 19, 2008, 9:19 pm
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On Wed, 19 Mar 2008 16:41:19 -0700, dummy wrote:
> $ow = \@in;
The two lines like this cause the problem. When a program uses "my @in"
inside a loop, it creates a new @in each time it goes around the loop.
Usually if you have
my $something
inside a loop, Perl destroys it at the end of the loop, but here you have
taken a reference to it, so Perl keeps it.
However, when you put "my @in" outside the loop, the above reference
points to the same old @in each time, so \@in points to the same old
thing each time, hence your problem.
You can fix this by copying the whole @in array into another array:
my @crud = @in;
$ow = \@crud;
But that may not be the optimal solution.
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Posted by Gunnar Hjalmarsson on March 19, 2008, 9:37 pm
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Ben Bullock wrote:
> when you put "my @in" outside the loop, the above reference
> points to the same old @in each time, so \@in points to the same old
> thing each time, hence your problem.
>
> You can fix this by copying the whole @in array into another array:
>
> my @crud = @in;
> $ow = \@crud;
Or simpler:
$ow = [ @in ];
--
Gunnar Hjalmarsson
Email: http://www.gunnar.cc/cgi-bin/contact.pl
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Posted by dummy on March 19, 2008, 9:51 pm
Please log in for more thread options On Thu, 20 Mar 2008 02:37:04 +0100, Gunnar Hjalmarsson
>Ben Bullock wrote:
>> when you put "my @in" outside the loop, the above reference
>> points to the same old @in each time, so \@in points to the same old
>> thing each time, hence your problem.
>>
>> You can fix this by copying the whole @in array into another array:
>>
>> my @crud = @in;
>> $ow = \@crud;
>
>Or simpler:
>
> $ow = [ @in ];
Thanks again!
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Posted by dummy on March 19, 2008, 10:23 pm
Please log in for more thread options On Thu, 20 Mar 2008 02:37:04 +0100, Gunnar Hjalmarsson
>Ben Bullock wrote:
>> when you put "my @in" outside the loop, the above reference
>> points to the same old @in each time, so \@in points to the same old
>> thing each time, hence your problem.
>>
>> You can fix this by copying the whole @in array into another array:
>>
>> my @crud = @in;
>> $ow = \@crud;
>
>Or simpler:
>
> $ow = [ @in ];
If that same code was used in several places in the same scope would it
create more than one anonymous array?
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Posted by Gunnar Hjalmarsson on March 20, 2008, 1:47 am
Please log in for more thread options dummy@phony.info wrote:
> On Thu, 20 Mar 2008 02:37:04 +0100, Gunnar Hjalmarsson
>>
>> $ow = [ @in ];
>
> If that same code was used in several places in the same scope would it
> create more than one anonymous array?
Yes. Each occurrence of [ @in ] would _copy_ @in into a new anonymous
array, to which $ow would become a reference. (I'm assuming that the
value of $i would not be the same.)
--
Gunnar Hjalmarsson
Email: http://www.gunnar.cc/cgi-bin/contact.pl
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