Tell us more of what you want to do. It may be that you want to build a dispatch table then iterate over the entered options. Something like:

use strict;
use warnings;
use Getopt::Long;

my %options;
my %dispatch = (
    a => \&doA,
    b => \&doB,
    c => \&doC,
);

GetOptions (\%options, 'a:s', 'b:s', 'c:s');

for my $option (keys %options) {
    $dispatch{$option}->($options{$option}) if exists $dispatch{$optio
+n};
}


sub doA {
    my ($param) = @_;
    
    print "Hello world\n";
}


sub doB {
    my ($param) = @_;
    
    print "Do da dispatch\n";
}


sub doC {
    my ($param) = @_;
    
    print "mu\n";
}
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given the command line '--a --b --c' prints:

mu
Hello world
Do da dispatch
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if ($a) {
  print "a was selected\n";
}
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my %opts;
GetOptions(map { ($_ => \$opts{$_}) } "a".."z");

$opts{$_} and print "$_ was selected\n" for "a".."z";
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The problem is that , there are more than 30 options, and I dont want to write like 30 if statements to get the selected options. Is there any effective way to find this?

Thanks,
Tom

Using runrig's example:

my %opts;
GetOptions(map { ($_ => \$opts{$_}) } "a".."z");
my @selected = grep { $opts{$_} } keys %opts;
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Thanks much.
-Tom

Should you decide to go with a dispatch table, the following may be helpful: Implementing Dispatch Tables