PERL Beginners - Can't create 2d array in Perl

Author

Can't create 2d array in Perl

Gregg Allen

2006-08-29, 9:57 pm

Hi:

I would like to read a tab delimited text file created in Excel into
a 2d array. I don't understand why the following doesn't work. The
$i and $j, along with the print statement, are only for debugging
purposes.

It prints:

Can't use string ("") as an ARRAY ref while "strict refs" in use at
file_vars.pl line 30, <FH> line 2.

Gregg Allen

****************************************
*****************
#!/usr/bin/perl -w

use strict;

my @arr ;

my $i = $ARGV[0];
my $j = $ARGV[1];

print $i . " \t" . $j . "\n";

open(FH,"<0817L.txt") or die "cannot open !$\n";

while(<FH> )
{

push @arr , split /\t/ ;

}

print $arr[$i][$j];

Klaus

2006-08-29, 9:57 pm

Gregg Allen wrote:
> I would like to read a tab delimited text file created in Excel into
> a 2d array. I don't understand why the following doesn't work.
> It prints:
> Can't use string ("") as an ARRAY ref while "strict refs" in use at
> file_vars.pl line 30, <FH> line 2.

[snip]

> while(<FH> )
> {
> push @arr , split /\t/ ;

You just need a pair of "[" ... "]" around "split /\t/", that's all:
push @arr, [ split /\t/ ];

(for reference --> see perldoc perldsc)

> }
>
> print $arr[$i][$j];

Mumia W.

2006-08-29, 9:57 pm

On 08/29/2006 07:01 PM, Gregg Allen wrote:
> Hi:
>
>
> I would like to read a tab delimited text file created in Excel into a
> 2d array. I don't understand why the following doesn't work. The $i
> and $j, along with the print statement, are only for debugging purposes.
>
> It prints:
>
>
> Can't use string ("") as an ARRAY ref while "strict refs" in use at
> file_vars.pl line 30, <FH> line 2.
>
> Gregg Allen
>
> ****************************************
*****************
> #!/usr/bin/perl -w
>
>
> use strict;
>
>
> my @arr ;
>
> my $i = $ARGV[0];
> my $j = $ARGV[1];
>
> print $i . " \t" . $j . "\n";
>
>
> open(FH,"<0817L.txt") or die "cannot open !$\n";
>
> while(<FH> )
> {
>
> push @arr , split /\t/ ;
>
> }
>
>
> print $arr[$i][$j];
>
>

I'm really

about what $i and $j are supposed to be,
but I might do it this way:

use strict;
use warnings;
use File::Slurp;
use Data::Dumper;

my @arr = map [ split /\t/ ], read_file('0817L.txt');
print Dumper(\@arr);

__END__

WARNING: UNTESTED CODE

Jeff Pang

2006-08-29, 9:57 pm

>
>while(<FH> )
>{
>
>push @arr , split /\t/ ;
>
>}
>
>

Hello,
Here you don't create a 2d array.Maybe you want this:

while(<FH> ) {
push @arry,[split/\t/];
}

Then each element of @arry is a anonymous array.You can access the anonymous array's elements as:

print $arry[0]->[0];

Hope this helps.

--
Jeff Pang
NetEase AntiSpam Team
http://corp.netease.com

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