Re: dimensioning arrays

hi, after your replies (thanks) I'm thinking about this:


#/usr/bin/perl
$nx=10;
$ny=5;

$initialisation = 0;

foreach $i (0..$nx) {
   foreach $j (0..$ny) {
      $a[$i][$j] = $initialisation;
   }
}

$a[1][1] = 2;

&subro($nx,\@a,$ny);

sub subro($nx,\@a,$ny) {

my $nx = shift;
my @a = @{shift}; #should be wrong...
my $ny = shift;

print "$a[1][1]\n";
print "$nx\n";
print "$ny\n";

}
[download]

I saw the @{shift} use in some node around, but I get an error...
How do i fix it?
rob

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Re: Re: dimensioning arrays by Gloom (Monk) on Feb 16, 2001 at 16:31 UTC
@{shift} may means @{'shift'} or @shift : it's ambiguous. be more sharp by adding "()" after shift. `... my $nx = shift; my @a = @{shift()}; # This should resolve your problem my $ny = shift; ...` [download] ________________________ Hope this helps	[reply] [d/l]
Re: Re: Re: dimensioning arrays by Anonymous Monk on Feb 16, 2001 at 16:54 UTC
Thanks, Now it works. It would be nice for me to have a general subroutine `sub initialise(\@dimensions,$initialisation_value,\@matrix)` [download] that gives back an initalised matrix of n-dimensions. I'll try as learning exercise, if it is not straightforward for someone to write it down here. There's a lot to learn from a snippet of code..:) rob	[reply] [d/l]
general solution Re: Re: Re: Re: dimensioning arrays by andye (Curate) on Feb 17, 2001 at 01:18 UTC
This is a solution. Not very efficient though (sorry)... but I found it interesting. `sub ar_init { my $shift = shift ; (defined $_[0]) ? [ map { ar_init(@_) } (1..$shift) ] : $shift ; } my $array_ref = ar_init(3, 2, 4, 'pop '); print $array_ref->[2][0][3]` [download] Since lists are 'flattened' in subroutine calls, you could put the dimensions in an array `@dim = (3, 2, 4)` and call it using `ar_init(@dim, 'foo')` - it would have the same effect. Note that the whole thing is constructed using references - you'll need to understand references for whatever solution you use. I like the explanation of reference syntax in _Effective_Perl_Programming_.	[reply] [d/l] [select]