Re: what is @$varname in perl

It seems like you're writing your arrays as array references just so you can avoid creating a reference out of a non-reference.

You have:

    foreach $line (@lines){
        chomp $line;
        $count++;
        next unless $count; # skip header in csv 
        my $row;
        @$row = split(/,/, $line );
        push @$sheet2 , $row;
    }
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But if you ask me, it'd be tons more clear if you did this:

my @sheet2 = ()

# ....
    
    foreach $line (@lines){
        chomp $line;
        $count++;
        next unless $count; # skip header in csv 
        my @row = ();
        @row = split(/,/, $line );
        push @sheet2 , \@row;
    }
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Another example is:

@$sheet2 = ();
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Should be:

@sheet2 = ();
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$sheet2 = [];
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It seems to me you're conflating scalars, arrays, and references. Cleaning up the code and being consistent will go a long way in dispelling your confusion.

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Re^2: what is @$varname in perl by sandy105 (Scribe) on Jul 03, 2014 at 12:10 UTC
i read up on reference and understand a scalar is assigned as reference : `my @array = (1, 2, 3, 'four'); my $reference = \@array;` [download] i modified using your suggestion as below `foreach $line (@lines){ chomp $line; $count++; next unless $count; my @row = (); @row = split(/,/, $line ); push @sheet2 , \@row; } foreach my $row ( sort {$a->[0] cmp $b->[0] \|\| $a->[1] cmp $b- +>[1]} @sheet2 ) #sorting based on date ,then stockcode { chomp $row; print hanw join (',', @$row ),"\n"; }` [download] then why assign @sheet2 as reference	[reply] [d/l] [select]
Re^3: what is @$varname in perl by 2teez (Vicar) on Jul 03, 2014 at 15:35 UTC
this : `... my $row; @$row = split(/,/, $line ); push @$sheet2 , $row; ...` [download] OR `... my @row = (); @row = split(/,/, $line ); push @sheet2 , \@row; ...` [download] Could be written like this in one line instead of three `... push @sheet2, [ split(/,/, $line ) ]; ...` [download] And there is no need for the array variable row at all. You could use Data::Dumper to view your variable @sheet2 to confirm. If you tell me, I'll forget. If you show me, I'll remember. if you involve me, I'll understand. --- Author unknown to me	[reply] [d/l] [select]
Re^3: what is @$varname in perl by perlfan (Parson) on Jul 04, 2014 at 03:18 UTC
`push @sheet2 , \@row;` [download] You're pushing a reference to @row as an item into @sheet2. In order to create complex data structures (array of arrays, array of hashes, etc) you need to assign references.	[reply] [d/l]