Home Accessibility Courses Twitter The Mouth Facebook Resources Site Map About Us Contact
Python, Lua and Tcl - public course schedule [here]
Private courses on your site - see [here]
Please ask about maintenance training for Perl, PHP, Java, C, C++, Ruby, MySQL and Linux / Tomcat systems
Use of hashes in Perl / CGI
Hashes example from a Well House Consultants training course
More on Hashes [link]

This example is described in the following article(s):
   • Why would you want to use a Perl hash? - [link]

If you're searching for a page where you can run this program, select here

Source code: blx.pl Module: P211
#!/usr/bin/env perl

# Use of hashes in Perl / CGI

print "Content-type: text/plain\n\n";

while (<DATA>) {
        ($letter,$descript) = /^(\w) - (.*)/;
        $section{$letter} = $descript;

open FH,"/home/wellho/public_html/resources/mtable.txt";
while (<FH>) {
        ($ref,$about) = split(/\s+/,$_,2);
        $lookup{$ref} = $about;

open FH,"/home/wellho/include/bloglinks.txt";
while (<FH>) {
        ($ref,$mod) = split;

open FH,"/home/wellho/include/bloglinks.txt";
while (<FH>) {
        ($ref,$mod) = split;
        $latest{$mod} = $ref;

open FH,"/home/wellho/include/bloglinks.txt";
while (<FH>) {
        ($ref,$mod) = split;
        $keyletter = substr($mod,0,1);
        if ($section{$keyletter}) {
                if ($thisarticle{$ref}{$keyletter}++ == 0) {
        } else {

# When did I last talk about THAT?

print "\nWhen did I last talk about THAT?\n";
for (sort {$latest{$b} <=> $latest{$a}} keys(%latest)) {
        print "$_ - $latest{$_} - $lookup{$_}\n";

# How many times have I talked about THAT?

print "\nHow many times have I talked about THAT?\n";
for (sort {$counter{$a} <=> $counter{$b}} keys(%counter)) {
        print "$_ - $counter{$_} - $lookup{$_}\n";

# How many times have I talked about THAT - by major section

print "\nHow many times have I talked about THAT - by major section\n";
for (sort {$sectcounter{$b} <=> $sectcounter{$a}} keys(%sectcounter)) {
        if (/^.$/) {
                print "$_ - $sectcounter{$_} - $section{$_}\n";
        } else {
                print "$_ - $sectcounter{$_} - $lookup{$_}\n";

# What have I NEVER talked about?
print "\nWhat have I NEVER talked about?\n";
for (keys %lookup) {
        unless ($counter{$_}) {
                print "$_ - $lookup{$_}\n";
print "\n";

A - Web Server Deployment - Linux, Apache Web Server and Tomcat
H - PHP programming and web techniques using PHP
Y - Python programming
U - Programming in Lua
T - Tcl, Tcl/Tk and Expect
P - The Perl programming language
S - SQL, including MySQL and SQLite
G - Non-technical issues
Q - General Technical Topics
W - HTML and Web Page Design
C - C and C++ Programming
R - Ruby Programming
M - Well House Manor - our hotel and training centre
J - Java and Java Programming

Learn about this subject
This module and example are covered on the following public courses:
 * Perl Programming
 * Perl bootcamp
 * Learning to program in Perl
 * Perl Programming
Also available on on site courses for larger groups

Books covering this topic
Yes. We have over 700 books in our library. Books covering Perl are listed here and when you've selected a relevant book we'll link you on to Amazon to order.

Other Examples
This example comes from our "Hashes" training module. You'll find a description of the topic and some other closely related examples on the "Hashes" module index page.

Full description of the source code
You can learn more about this example on the training courses listed on this page, on which you'll be given a full set of training notes.

Many other training modules are available for download (for limited use) from our download centre under an Open Training Notes License.

Other resources
• Our Solutions centre provides a number of longer technical articles.
• Our Opentalk forum archive provides a question and answer centre.
The Horse's mouth provides a daily tip or thought.
• Further resources are available via the resources centre.
• All of these resources can be searched through through our search engine
• And there's a global index here.

Purpose of this website
This is a sample program, class demonstration or answer from a training course. It's main purpose is to provide an after-course service to customers who have attended our public private or on site courses, but the examples are made generally available under conditions described below.

Web site author
This web site is written and maintained by Well House Consultants.

Conditions of use
Past attendees on our training courses are welcome to use individual examples in the course of their programming, but must check the examples they use to ensure that they are suitable for their job. Remember that some of our examples show you how not to do things - check in your notes. Well House Consultants take no responsibility for the suitability of these example programs to customer's needs.

This program is copyright Well House Consultants Ltd. You are forbidden from using it for running your own training courses without our prior written permission. See our page on courseware provision for more details.

Any of our images within this code may NOT be reused on a public URL without our prior permission. For Bona Fide personal use, we will often grant you permission provided that you provide a link back. Commercial use on a website will incur a license fee for each image used - details on request.

You can Add a comment or ranking to this page

© WELL HOUSE CONSULTANTS LTD., 2018: Well House Manor • 48 Spa Road • Melksham, Wiltshire • United Kingdom • SN12 7NY
PH: 01225 708225 • FAX: 01225 793803 • EMAIL: info@wellho.net • WEB: http://www.wellho.net • SKYPE: wellho

PAGE: http://www.wellho.net/resources/ex.php4 • PAGE BUILT: Sun Jan 31 13:04:01 2016 • BUILD SYSTEM: WomanWithCat