How to create hash dynamically in perl?

Shell Programming and Scripting
1

Hi,

I have one file name file.txt

It has the following contents:

#File Contents

StartTime,EndTime,COUNTER1,COUNTER2,COUNTER3
12:13,12:14,0,1,0

The output should be like this:

StartTime: 12:13
ENDTIME:  12:14
COUNTER1: 0
COUNTER2: 1
COUNTER3: 0

I have to create hash dynamically.

How can i create a hash dynamically and get the above output?

I tried in Google but could not get satisfactory result.

Regards
Vanitha

2

I don't know much about perl hashes (yet), but one could also solve that problem like this:

$ perl -lne '{@x=split(/,/,$_), $a=1 if /^Start/;
              @y=split(/,/,$_) if $a == 1}
              END{ for (0..4) {print "$x[$_]: $y[$_]"}}' file
StartTime: 12:13
EndTime: 12:14
COUNTER1: 0
COUNTER2: 1
COUNTER3: 0
$
3

Maybe not the most efficient algorithm, but for most applications it should do:

$ cat hash.pl
#!/usr/bin/perl

use strict;
use warnings;

use Data::Dumper;

my $line;
my %hash;
$line = <DATA>;
chomp $line;
my @keys = split /,/, $line;
while ( $line = <DATA> ) {
    chomp $line;
    my @val = split /,/, $line;
    for ( my $i = 0 ; $i <= $#val ; $i++ ) {
        push @{ $hash{ $keys[$i] } }, $val[$i];
    }
}

print Data::Dumper->Dump( [ \%hash ], [qw/hash/] );

__DATA__
StartTime,EndTime,COUNTER1,COUNTER2,COUNTER3
12:13,12:14,0,1,0
$
$
$
$ perl hash.pl
$hash = {
          'COUNTER3' => [
                          '0'
                        ],
          'COUNTER1' => [
                          '0'
                        ],
          'COUNTER2' => [
                          '1'
                        ],
          'EndTime' => [
                         '12:14'
                       ],
          'StartTime' => [
                           '12:13'
                         ]
        };