It would be a lot easier to help if you told us what you were trying to achieve instead of just giving us non-working code and expecting us to work it out for ourselves.

Also, adding use strict and use warnings to your code will help Perl to help you find the problems.

I'm guessing, but is this something like what you wanted?

#! /usr/bin/perl

use strict;
use warnings;

my @a;
my $b = "abefcdghijklmn" ;

$a[0]->[0] = "start 0" ;
$a[1]->[0] = "start 1" ;

for(my $i = 0; $i < 14; $i += 2) {
    my ($foo, $bar) = unpack("x$i A1 A1", $b) ;
    push @{$a[0]}, $foo;
    push @{$a[1]}, $bar;
}

foreach ( @{$a[0]} ) {
    print "$_\n" ;
}
[download]

If that is what you want, then it's probably more maintainable if it's written something like this:

#! /usr/bin/perl

use strict;
use warnings;

my @a;
my $b = "abefcdghijklmn" ;

$a[0]->[0] = "start 0" ;
$a[1]->[0] = "start 1" ;

my @chars = split //, $b;

while (@chars) {
  push @{$a[0]}, shift @chars;
  push @{$a[1]}, shift @chars;
}

foreach ( @{$a[0]} ) {
    print "$_\n" ;
}
[download]

yes, thats what I need (sorry for my short explanation).
Is there no way to insert these values directly into those array refs with push or something else ?

Is there no way to insert these values directly into those array refs with push or something else?

Well, you could directly assign each value to the next element off the end of each array with code like this:

($a[0][@{$a[0]}], $a[1][@{$a[1]}]) = unpack("x$i A1 A1", $b) ;
[download]

But that's horrible!

--
<http://dave.org.uk>

"The first rule of Perl club is you do not talk about Perl club."
-- Chip Salzenberg

Maybe this more succinctly captures the essence of what your code has to do?

#! perl -slw
use strict;
use Data::Dumper;

my $b = "abefcdghijklmn";
my @a;
@{ $a[ 0 ] } = ( 'start 0', unpack '(A1x)*', $b );
@{ $a[ 1 ] } = ( 'start 1', unpack '(xA1)*', $b );

print Dumper \@a;
__END__
C:\test>539664
$VAR1 = [
    [ 'start 0', 'a', 'e', 'c', 'g', 'i', 'k', 'm' ],
    [ 'start 1', 'b', 'f', 'd', 'h', 'j', 'l', 'n' ]
];
[download]

Better yet.

#! perl -slw
use strict;
use Data::Dumper;

my $b = "abefcdghijklmn";
my @a = (
    [ 'start 0', unpack '(A1x)*', $b ],
    [ 'start 1', unpack '(xA1)*', $b ]
);

print Dumper \@a;
__END__
C:\test>539664
$VAR1 = [
    [ 'start 0', 'a', 'e', 'c', 'g', 'i', 'k', 'm' ],
    [ 'start 1', 'b', 'f', 'd', 'h', 'j', 'l', 'n' ]
];
[download]

---

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

Lingua non convalesco, consenesco et abolesco. -- Rule 1 has a caveat! -- Who broke the cabal?

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.

Here's another way, although it uses an additional temporary variable...

my $b = "abefcdghijklmn";
my @a = (['start 0'], ['start 1']);
my $i = 0;
push @{ $a[$i++ % 2] }, $_ for unpack('(A)*', $b);
[download]

---

Jeff japhy Pinyan, P.L., P.M., P.O.D, X.S.: Perl, regex, and perl hacker
How can we ever be the sold short or the cheated, we who for every service have long ago been overpaid? ~~ Meister Eckhart

THATS IT!!!!!

Thanks a lot
Luca

The parent requires Perl 5.8. The following is more portable:

my @a = (
    [ 'start 0', $b =~ /(.)./g ],
    [ 'start 1', $b =~ /.(.)/g ],
);
[download]

$b = "abefcdghijklmn" ;

$a[0]->[0] = "start 0" ;
$a[1]->[0] = "start 1" ;

my @b = unpack 'A' x 14, $b;

while (@b) {
    push @{$a[0]}, shift @b;
    push @{$a[1]}, shift @b;
}

foreach ( @{$a[0]} ) {
    print "$_\n" ;
}
[download]

#! /usr/bin/perl
#
use strict ;
use warnings ;
my $b = "abcdefghijklm" ;

my @a ;

$a[0]->[0] = "start 0" ;
$a[1]->[0] = "start 1" ;

for(my $i = 0; $i < 14; $i += 2) {
    push (@{$a[0]}, $_) for unpack("x$i A1", $b) ;
    push (@{$a[1]}, $_) for unpack("x".($i+1)." A1", $b) ;
}

foreach ( @{$a[0]} ) {
    print "$_\n" ;
}
foreach ( @{$a[1]} ) {
    print "$_\n" ;
}
[download]

Yuck! Using unpack is inappropriate here! Use substr:

push(@{$a[$_%2]}, substr($b, $_, 1))
   for 0..13;
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push(@{$a[0]}, $b =~ /(.)./g);
push(@{$a[1]}, $b =~ /.(.)/g);
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my $t = 1;
push(@{$a[$t ^= 1]}, $_)
   foreach $b =~ /(.)/g;
[download]

By the way, you shouldn't name your variables $b (or $a). These are reserved for sort.