Hash of lists in Perl

For 2023 - we are now fully retired from IT training.
We have made many, many friends over 25 years of teaching about Python, Tcl, Perl, PHP, Lua, Java, C and C++ - and MySQL, Linux and Solaris/SunOS too. Our training notes are now very much out of date, but due to upward compatability most of our examples remain operational and even relevant ad you are welcome to make us if them "as seen" and at your own risk.

Lisa and I (Graham) now live in what was our training centre in Melksham - happy to meet with former delegates here - but do check ahead before coming round. We are far from inactive - rather, enjoying the times that we are retired but still healthy enough in mind and body to be active!

I am also active in many other area and still look after a lot of web sites - you can find an index ((here))

Here's a short program that reads data into a hash of lists, sorts the keys and displays output data - a simple Perl program showing powerful capabilities of the language.



while () {

        my ($name,@temporary) = split;

        $want{$name} = \@temporary;

        } 



foreach $person (sort keys %want) {

        print $person," ",$want{$person}[0]," ",$#{$want{$person}}+1,"\n";

        }



__DATA__

antonia Perl XML PHP Tcl/Tk MySQL

ethel MySQL Perl Tcl/Tk ASP

iris  Perl MySQL Java Tcl/Tk

olivia  MySQL Python ASP PHP

uva MySQL Perl Java PHP

adam Tcl/Tk Perl Python MySQL

ed Ruby Perl Java PHP 

ivan Ruby Java Perl Tcl/Tk MySQL

orpheus MySQL Ruby Tcl/Tk XML

ulsyees Java PHP Perl

Results:



adam Tcl/Tk 4

antonia Perl 5

ed Ruby 4

ethel MySQL 4

iris Perl 4

ivan Ruby 5

olivia MySQL 4

orpheus MySQL 4

ulsyees Java 3

uva MySQL 4

A little demo I wrote today while talking about more complex data structures.

Things always turn out so easy in Perl!
(written 2004-09-09, updated 2006-06-05)

Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles

P217 - Perl - More than Simple Lists and Hashes!
  [293] Course follow-ups - (2005-04-27)
  [1514] Autovivification - the magic appearance of variables in Perl - (2008-01-21)
  [2241] Perl references - $$var and \$var notations - (2009-06-15)
  [2840] Just pass a pointer - do not duplicate the data - (2010-06-30)
  [2877] Further more advanced Perl examples - (2010-07-19)
  [2996] Copying - duplicating data, or just adding a name? Perl and Python compared - (2010-10-12)
  [3007] Setting up a matrix of data (2D array) for processing in your program - (2010-10-21)
  [3072] Finding elements common to many lists / arrays - (2010-11-26)
  [3105] Adventure with references to lists and lists of references - (2010-12-26)
  [3118] Arrays of arrays - or 2D arrays. How to program tables. - (2011-01-02)
  [3399] From fish, loaves and apples to money, plastic cards and BACS (Perl references explained) - (2011-08-20)
  [3406] Not multidimentional arrays - but lists of lists. Much more flexible. Perl! - (2011-08-26)
  [3444] Take the dog on a lead - do not carry her. Perl references. - (2011-09-17)
  [3577] How to do multidimensional arrays (or rather lists and hashes) in Perl - (2012-01-14)
  [3906] Taking the lead, not the dog, for a walk. - (2012-10-28)

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Effective fundraising
Near and far security
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Serious subject
Hash of lists in Perl
Do languages change?
A Thousand and four words
Take the train to training
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This is a page archived from The Horse's Mouth at http://www.wellho.net/horse/ - the diary and writings of Graham Ellis. Every attempt was made to provide current information at the time the page was written, but things do move forward in our business - new software releases, price changes, new techniques. Please check back via our main site for current courses, prices, versions, etc - any mention of a price in "The Horse's Mouth" cannot be taken as an offer to supply at that price.

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