G'day Priti24,

Perl already provides the functionality you describe. So, unless you have a specific reason for re-inventing the wheel (which may be perfectly valid but isn't addressed in your post), you can use code like this to achieve what you're after.

#!/usr/bin/env perl

use strict;
use warnings;

my %ex = (
    37 => 'p', 41 => 't', 23 => 's', 52 => 'm', 44 => 'a', 65 => 'q',
    26 => 'd', 88 => 'o', 99 => 'g', 100 => 'l', 101 => 'f', 201 => 'i
+'
); 

print 'Enter the key you want to search for: ';
my $k = <>;
chomp $k;

if (exists $ex{$k}) {
    print "The key '$k' has the value: $ex{$k}\n";
}
else {
    print "The key '$k' doesn't exist.\n";
}
[download]

Here it is in action with the three keys you mention (37, 47 & 101):

$ pm_hash_search.pl
Enter the key you want to search for: 37
The key '37' has the value: p

$ pm_hash_search.pl
Enter the key you want to search for: 47
The key '47' doesn't exist.

$ pm_hash_search.pl
Enter the key you want to search for: 101
The key '101' has the value: f
[download]

Here's some of the things you could have done better in the code you provided:

• Let Perl tell you when you're doing something potentially problematic, or just plain wrong, with strict and warnings. See usage in my code.
• Declare your variables. my is used most often - see my %ex and my $k in my code. With no declarations, all your variables become global which has all sorts of implications and is basically a headache you don't need to have. (There are other ways to declare variables - see perlsub for details.)
• You call your subroutine with an argument (perlhash($k)) but don't read that argument in the subroutine code. In this instance, my $k = shift; would have been sufficient; for multiple arguments, use something like my ($arg1, ..., $argN) = @_; - see perlsub for details.
• It's easy to mistype, misread or miscount the exact number of arrayrefs in @buckets = ( [],[],[],[],[],[],[],[],[],[] );. You can use the x operator to avoid all three types of problems: @buckets = ([]) x 10; - see perlop for details.
• When you read user input (typed from the keyboard) you'll get all the keystrokes including the final return. Use chomp to remove this (as I did in my code).
• Your code would be easier to read if it was laid out a little better - perlstyle has some suggestions regarding this.