Problemm with adding hash to hash of hash

[retfos]

I wrote a subroutine to create a hash with numbers of transitions between states makred by binary codes in string. Length of codes is passed by parameter $rank and the second parameter is the string to analize. That is the code:

sub get_prob{
my ($file_content,$rank)=@_;
my %hash;
my %row;

$start_portion=get_portion_of_string($file_content,0,$rank);
$actual_portion=$start_portion;
$hash{$actual_portion}->{$actual_portion}=0;
$i=1;
$size=length($file_content);

while($i+$rank<=$size){
$next_portion=substr($actual_portion,1,$rank-1);
$next_portion.=substr($file_content,$i+$rank-1,1);

if (exists $hash{$actual_portion}{$next_portion}){
# there is transition in hash
$hash{$actual_portion}->{$next_portion}+=1;

} else { #there isn't transition in hash
my %row;
$hash{$next_portion}=$row;
while( my ($k, $v) = each %hash ) {
$row->{$k}=0;

}
$hash{$next_portion}=%row;

while ( my ($k, $v) = each %hash ){
$hash{$k}->{$next_portion}=0;
#if ($actual_portion ne $start_portion){
$hash{$start_portion}->{$next_portion}=0;}
}
$hash{$actual_portion}->{$next_portion}=1;
}
$i++;
$actual_portion=$next_portion;
}


return %hash;


}

I think that the problem is that I'm adding to the %hash the reference to %row instead of hash and when i'm changing value of field in row i'm changing value in all added rows. I tried to resolve that but I only get an errors. Can anybody know how to do this correct??

PS I'm sorry but my english isn't perfect.

 

[MillerH]

Making your code a little more readable first gives us:

[url=http://perldoc.perl.org/functions/sub.html][black][b]sub[/b][/black][/url] [maroon]get_prob[/maroon] [red]{[/red]
	[url=http://perldoc.perl.org/functions/my.html][black][b]my[/b][/black][/url] [red]([/red][blue]$file_content[/blue],[blue]$rank[/blue][red])[/red] = [blue]@_[/blue][red];[/red]
	[black][b]my[/b][/black] [blue]%hash[/blue][red];[/red]
	[black][b]my[/b][/black] [blue]%row[/blue][red];[/red]

	[blue]$start_portion[/blue] = [maroon]get_portion_of_string[/maroon][red]([/red][blue]$file_content[/blue],[fuchsia]0[/fuchsia],[blue]$rank[/blue][red])[/red][red];[/red]
	[blue]$actual_portion[/blue] = [blue]$start_portion[/blue][red];[/red]
	[blue]$hash[/blue][red]{[/red][blue]$actual_portion[/blue][red]}[/red]->[red]{[/red][blue]$actual_portion[/blue][red]}[/red] = [fuchsia]0[/fuchsia][red];[/red]

	[blue]$i[/blue]=[fuchsia]1[/fuchsia][red];[/red]
	[blue]$size[/blue] = [url=http://perldoc.perl.org/functions/length.html][black][b]length[/b][/black][/url][red]([/red][blue]$file_content[/blue][red])[/red][red];[/red]

	[olive][b]while[/b][/olive][red]([/red][blue]$i[/blue]+[blue]$rank[/blue] <= [blue]$size[/blue][red])[/red] [red]{[/red]
		[blue]$next_portion[/blue] = [url=http://perldoc.perl.org/functions/substr.html][black][b]substr[/b][/black][/url][red]([/red][blue]$actual_portion[/blue],[fuchsia]1[/fuchsia],[blue]$rank[/blue]-[fuchsia]1[/fuchsia][red])[/red][red];[/red]
		[blue]$next_portion[/blue] .= [black][b]substr[/b][/black][red]([/red][blue]$file_content[/blue],[blue]$i[/blue]+[blue]$rank[/blue]-[fuchsia]1[/fuchsia],[fuchsia]1[/fuchsia][red])[/red][red];[/red]

		[olive][b]if[/b][/olive] [red]([/red][url=http://perldoc.perl.org/functions/exists.html][black][b]exists[/b][/black][/url] [blue]$hash[/blue][red]{[/red][blue]$actual_portion[/blue][red]}[/red][red]{[/red][blue]$next_portion[/blue][red]}[/red][red])[/red] [red]{[/red]
			[gray][i]# there is transition in hash[/i][/gray]
			[blue]$hash[/blue][red]{[/red][blue]$actual_portion[/blue][red]}[/red]->[red]{[/red][blue]$next_portion[/blue][red]}[/red] += [fuchsia]1[/fuchsia][red];[/red]

		[red]}[/red] [olive][b]else[/b][/olive] [red]{[/red] [gray][i]#there isn't transition in hash[/i][/gray]
			[black][b]my[/b][/black] [blue]%row[/blue][red];[/red]
			[blue]$hash[/blue][red]{[/red][blue]$next_portion[/blue][red]}[/red] = [blue]$row[/blue][red];[/red]
			[olive][b]while[/b][/olive][red]([/red] [black][b]my[/b][/black] [red]([/red][blue]$k[/blue], [blue]$v[/blue][red])[/red] = [url=http://perldoc.perl.org/functions/each.html][black][b]each[/b][/black][/url] [blue]%hash[/blue] [red])[/red] [red]{[/red]
				[blue]$row[/blue]->[red]{[/red][blue]$k[/blue][red]}[/red]=[fuchsia]0[/fuchsia][red];[/red]
			[red]}[/red]
			
			[blue]$hash[/blue][red]{[/red][blue]$next_portion[/blue][red]}[/red] = [blue]%row[/blue][red];[/red]

			[olive][b]while[/b][/olive] [red]([/red] [black][b]my[/b][/black] [red]([/red][blue]$k[/blue], [blue]$v[/blue][red])[/red] = [black][b]each[/b][/black] [blue]%hash[/blue] [red])[/red] [red]{[/red]
				[blue]$hash[/blue][red]{[/red][blue]$k[/blue][red]}[/red]->[red]{[/red][blue]$next_portion[/blue][red]}[/red] = [fuchsia]0[/fuchsia][red];[/red]
				[gray][i]#if ($actual_portion ne $start_portion) {[/i][/gray]
				[gray][i]#	$hash{$start_portion}->{$next_portion}=0;[/i][/gray]
				[gray][i]#}[/i][/gray]
			[red]}[/red]
			[blue]$hash[/blue][red]{[/red][blue]$actual_portion[/blue][red]}[/red]->[red]{[/red][blue]$next_portion[/blue][red]}[/red] = [fuchsia]1[/fuchsia][red];[/red]
		[red]}[/red]
		[blue]$i[/blue]++[red];[/red]
		[blue]$actual_portion[/blue]=[blue]$next_portion[/blue][red];[/red]
	[red]}[/red]

	[url=http://perldoc.perl.org/functions/return.html][black][b]return[/b][/black][/url] [blue]%hash[/blue][red];[/red]
[red]}[/red]

There are some obvious problems starting around the second "my %row;" declaration. In the following 4 lines you interchangably refer to the hash %row and also the hash reference $row. This is most likely a bug.

Ultimately, the biggest thing that we can advise you to do us to "use strict;" and declare all your variables. This is always important, but even more so when dealing with complex data structures. It would point out obvious scoping problems such as using $row instead of %row as the former is not defined.

- Miller