You probably want to use a hash for that.

my %color = (
    red  => 0xFF0000,
    blue => 0x0000FF,
# . . .
);
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Thanks a lot for the message. Its a bit unclear to me as how can I use this information in my case. I have about 7000 unique identifiers and I need 7000 unique colors for that. Thanks Nagesh

There are 753 unique colours in the openwin rgb.txt on the machine nearest my thumb and the following code indexes them by unique name into a hash of hash :

#!/usr/bin/perl

use Data::Dumper;
open RGB, '</usr/openwin/lib/rgb.txt';

my %rgb = ();
while ( <RGB> ) {
    if ( /^(\d+)\s*(\d+)\s*(\d+)\s*(.*)$/ ) {
        $rgb{ $4 }{ red } = $1;
        $rgb{ $4 }{ green } = $2;
        $rgb{ $4 }{ blue } = $3;
    }
}
print Dumper( \%rgb );
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output:
Read more... (85 kB)

See chr and ord. You can also use unpack to retrieve the character codes for a string in one go:

$ perl -le 'print for unpack("C*","foo")'
102
111
111
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Thanks a lot. Thats exactly what I am looking for. Will try it and see whether I can make use of this methods. Cheers Nagesh

Using package constant to define your named constants, is somewhat more efficient that using a hash to perform the mapping:

#! perl -slw
use strict;
use Benchmark qw[ cmpthese ];

package C;

use constant {
    RED     => 0xFF0000,
    BLUE    => 0x00FF00,
    GREEN   => 0x0000FF,
};

package main;

use constant {
    RED     => 0xFF0000,
    BLUE    => 0x00FF00,
    GREEN   => 0x0000FF,
};

my %colors = (
    RED     => 0xFF0000,
    BLUE    => 0x00FF00,
    GREEN   => 0x0000FF,
);

open STDERR, ">nul";

cmpthese -1, {
    hash    => sub{ warn $colors{ RED }, $colors{ BLUE }. $colors{ GRE
+EN }; },
    m_const => sub{ warn RED, BLUE. GREEN; },
    p_const => sub{ warn C::RED, C::BLUE. C::GREEN; },
};

__END__
P:\test>junk
            Rate    hash m_const p_const
hash    116531/s      --    -11%    -12%
m_const 130636/s     12%      --     -1%
p_const 132428/s     14%      1%      --

P:\test>junk
            Rate    hash p_const m_const
hash    116531/s      --     -9%    -10%
p_const 128577/s     10%      --     -1%
m_const 129366/s     11%      1%      --

P:\test>junk
            Rate    hash m_const p_const
hash    116642/s      --    -10%    -10%
m_const 129468/s     11%      --     -0%
p_const 129590/s     11%      0%      --
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If you're concerned with the namespace pollution of having 7000 constants in your main package (though if you make them all uppercase it precludes most possibilities of collisions), then you could place them into separate (short-named) package and invoke them via their full names as in m_const above.

Thanks for the posting

are you talking about this?

$nums = "123";
$val = $nums * 1;
print ("Value = $val\n");
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Thanks for the posting. Sorry for not being clearer. By string of letters i meant a name like "V$CEBPA". So if I can convert this string to a numerical value, I can use it to generate the color which will be unique to this identifier. Thanks Nagesh

Thanks. I completely missed the point! Please see Zaxo's post. You can basically attach a key to a value in a hash. Which should give what you want

-SK