Use of a sub to avoid repeating code

Programming Principles example from a Well House Consultants training course
More on Programming Principles [link]

This example is described in the following article(s):
• Do not copy and paste code - there are much better ways - [link]
• Perl and the Common Gateway Interface - out of fashion but still very useful? - [link]

Source code: algo Module: Q101

# This Perl example shows you how you can use a sub to avoid
# having to repeat a block of code. The algorithm to split a
# piece of text into individual letters, eliminate spaces, and
# join it back up again is needed several times, with a different
# joing string

sub wordsort {
        my ($incoming,$sep) = @_;
        @nlet = sort(map(lc,split(/\s*/,$incoming)));
        join($sep,@nlet);
        }

open (FH,"stationtables.tsv");
@about = <FH>;
for (@about) {
        ($name) = (split(/\t/))[1];
        $nk = wordsort($name,"");
        # print ("$name - $nk\n");
        $table{$name} = $nk;
        }

while (1) {
        print "Word: ";
        chop ($lookfor = <STDIN>);
        $regex = wordsort($lookfor,".*");
        for (sort keys(%table)) {
                if ($table{$_} =~ /$regex/) {
                        print "$_ - $table{$_}\n";
                }
        }
}

__END__

The program looks for a word in a place (station) name ...
a Christmas quiz! Here are some examples of it running:

bash-2.05b$ perl algo
Word: Christmas
King's Cross Thameslink - 'aceghiikklmnnorsssst
Swinton (Gr Manchester) - ()aceeghimnnnorrssttw
Word: Santa
Adlington (Lancs) - ()aacdgillnnnost
Aldermaston - aadelmnorst
Ancaster - aacenrst
Ardrossan South Beach - aaabcdehhnoorrssstu
Ardrossan Town - aadnnoorrsstw
Ashford International - aaadefhiilnnnoorrstt
Ashford International (Eurostar) - ()aaaadeefhiilnnnooorrrrsstttu
Banstead - aabdenst
Barlaston - aablnorst
Barnstaple - aabelnprst
Blaenau Ffestiniog - aabeeffgiilnnostu
Bramley (Hants) - ()aabehlmnrsty
Burnley Manchester Road - aabcdeeehlmnnorrrstuy
Canterbury East - aabceenrrsttuy
Carshalton - aachlnorst
Carshalton Beeches - aabcceeehhlnorsst
Cheltenham Spa - aaceehhlmnpst
Clacton on Sea - aaccelnnoost
Clapham (North Yorkshire) - ()aacehhhiklmnooprrrsty
Clarbeston Road - aabcdelnoorrst
Cobham & Stoke d'Abernon - &'aabbcdeehkmnnooorst
Dalston Kingsland - aaddgikllnnnosst
Deansgate - aadeegnst
Dumbarton East - aabdemnorsttu
Earlswood (West Midlands) - ()aadddeeillmnoorssstww
East Grinstead - aadeeginrsstt
East Malling - aaegillmnst
Elephant & Castle - &aaceeehllnpstt
Euxton Balshaw Lane - aaabeehllnnostuwx
Falkirk Grahamston - aaafghikklmnorrst
Gainsborough Central - aabcegghilnnoorrstu
Glasgow Central - aaceggllnorstw
Hamilton Square - aaehilmnoqrstu
Harrow & Wealdstone - &aadeehlnoorrstww
Hatfield & Stainforth - &aadeffhhiilnorsttt
Hayes & Harlington - &aaeghhilnnorsty
Headstone Lane - aadeeehlnnost
Lancaster - aacelnrst
Langwith-Whaley Thorns - -aaeghhhillnnorsttwwy
Leamington Spa - aaegilmnnopst
Lelant Saltings - aaegilllnnsstt
Leuchars (for St. Andrews) - ().aacdeefhlnorrrssstuw
Llanbister Road - aabdeillnorrst
Llansamlet - aaelllmnst
London St Pancras Domestic - aaccddeilmnnnoooprssstt
London Waterloo East - aadeellnnoooorsttw
Maesteg (Ewenny Road) - ()aadeeeegmnnorstwy
Maidstone Barracks - aaabcdeikmnorrsst
Maidstone East - aadeeimnosstt
Manchester Airport - aaceehimnoprrrstt
Manchester Oxford Road - aacddeefhmnooorrrstx
Manchester Piccadilly - aacccdeehiillmnprsty
Manchester United FC Halt - aaccdeeefhhilmnnrstttu
Manchester Victoria - aacceehiimnorrsttv
Market Rasen - aaeekmnrrst
Mountain Ash - aahimnnostu
Newark Castle - aaceeklnrstw
Newton (Lanarks) - ()aaeklnnnorstw
North Walsham - aahhlmnorstw
Oakengates - aaeegknost
Pontarddulais - aaddilnoprstu
Pontefract Tanshelf - aaceeffhlnnoprsttt
Prestwick International Airport - aaaceeiiiiklnnnoopprrrrsttttw
Queenstown Road (Battersea) - ()aaabdeeeennooqrrsstttuw
Rhoose Cardiff International Airport - aaaacdeeffhiiiilnnnooooprrrrrsttt
Rowlands Castle - aacdellnorsstw
Salford Central - aacdefllnorrst
Sanderstead - aaddeenrsst
Seaforth & Litherland - &aadeefhhillnorrstt
Seaton Carew - aaceenorstw
Southampton Airpt Parkway - aaaahikmnooppprrstttuwy
Southampton Central - aacehlmnnooprstttu
St Albans - aablnsst
St Albans Abbey - aaabbbelnssty
St Andrews Road - aaddenorrsstw
St Annes-on-the-Sea - ---aaeeehnnnossstt
St Leonards Warrior Square - aaadeeilnooqrrrrrssstuw
St Margarets (Gr London) - ()aadegglmnnoorrrsstt
St Pancras International - aaaaceiilnnnnoprrssttt
Stansted Airport - aadeinoprrssttt
Stapleton Road - aadelnooprstt
Stranraer - aaenrrrst
Stratford-upon-Avon - --aadfnnoooprrsttuv
Strathcarron - aachnorrrstt
Streatham Common - aacehmmmnoorstt
Sutton Parkway - aaknoprsttuwy
Talsarnau - aaalnrstu
Walthamstow Central - aaacehllmnorstttww
Walthamstow Queen's Road - 'aaadeehlmnooqrssttuww
Walton-on-Thames - --aaehlmnnoosttw
Wandsworth Road - aaddhnoorrstww
Wanstead Park - aaadeknprstw
Watton-at-Stone - --aaennoosttttw
West Hampstead Thameslink - aaadeeehhiklmmnpssstttw
Westgate-on-Sea - --aaeeegnossttw
Whatstandwell - aadehllnsttww
Ystrad Mynach - aacdhmnrstyy
Ystrad Rhondda - aadddhnorrsty
Word:

Learn about this subject

This module and example are covered on the following public courses:
* Learning to program in PHP
* Learning to program in Python
* Learning to Program in Java
* Learning to program in Lua
* Learning to program in Ruby
* Learning to program in Tcl
* Learning to Program in C
* Learning to program in C and C++
* Learning to program in Perl
* Learning to program in PHP
* Learning to program in C and C++
Also available on on site courses for larger groups

Books covering this topic

Yes. We have over 700 books in our library. Books covering all the subjects we teach 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 "Programming Principles" training module. You'll find a description of the topic and some other closely related examples on the "Programming Principles" 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.