note
kcott
<p>G'day [Priti24],</p>
<p>
Perl already provides the functionality you describe. So, unless you have a specific reason for <em>re-inventing the wheel</em> (which may be perfectly valid but isn't addressed in your post), you can use code like this to achieve what you're after.
</p>
<code>
#!/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";
}
</code>
<p>
Here it is in action with the three keys you mention (37, 47 & 101):
</p>
<code>
$ 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
</code>
<p>
Here's some of the things you could have done better in the code you provided:
</p>
<ul>
<li>
Let Perl tell you when you're doing something potentially problematic, or just plain wrong, with [http://perldoc.perl.org/strict.html|strict] and [http://perldoc.perl.org/warnings.html|warnings]. See usage in my code.
</li>
<li>
Declare your variables. [http://perldoc.perl.org/functions/my.html|my] is used most often - see <c>my %ex</c> and <c>my $k</c> in my code. With no declarations, all your variables become global which has all sorts of implications and is basically a headache you don't need to have. (There are other ways to declare variables - see [http://perldoc.perl.org/perlsub.html|perlsub] for details.)
</li>
<li>
You call your subroutine with an argument (<c>perlhash($k)</c>) but don't read that argument in the subroutine code. In this instance, <c>my $k = shift;</c> would have been sufficient; for multiple arguments, use something like <c>my ($arg1, ..., $argN) = @_;</c> - see [http://perldoc.perl.org/perlsub.html|perlsub] for details.
</li>
<li>
It's easy to mistype, misread or miscount the exact number of arrayrefs in <c>@buckets = ( [],[],[],[],[],[],[],[],[],[] );</c>. You can use the <c>x</c> operator to avoid all three types of problems: <c>@buckets = ([]) x 10;</c> - see [http://perldoc.perl.org/perlop.html|perlop] for details.
</li>
<li>
When you read user input (typed from the keyboard) you'll get all the keystrokes including the final return. Use [http://perldoc.perl.org/functions/chomp.html|chomp] to remove this (as I did in my code).
</li>
<li>
Your code would be easier to read if it was laid out a little better - [http://perldoc.perl.org/perlstyle.html|perlstyle] has some suggestions regarding this.
</li>
</ul>
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<div class="pmsig"><div class="pmsig-861371">
<p>-- Ken</p>
</div></div>
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