Home Accessibility Courses Twitter The Mouth Facebook Resources Site Map About Us Contact
 
For 2023 (and 2024 ...) - 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 Our training notes are now very much out of date, but due to upward compatability most of our examples remain operational and even relevant ad you are welcome to make us if them "as seen" and at your own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))
Revision / Summary of lists - Perl

We've started the third day of this week's Perl course with a revision of some features of lists ... posting here as there are some useful reminders (and I came back later to add more comments!)

# Revision / Summary of lists - Perl
 
$abc = 16; # single value
@abc = (16,14,12,11,10,8,7,2); # multiple values - a list
 
print "Single value is $abc\n";
print "Single value from \@abc $abc[2] (third element)\n";
print "Whole list \@abc: @abc \n";
 
# ------ Processing lists as a whole via functions;
# ------ grep to FILTER
# ------ map to transform every element
 
print "process whole list ...";
# Regulr expression - a 1 follwed by another character NOT a 0 1 or 2
@teens = grep(/^1[^012]/,@abc);
print "Teenagers are @teens\n";
 
@nextyear = map($_+1,@abc); # Add 1 to each element
push @nextyear,1;
print "Next year ages will be @nextyear\n";
 
# ------ $#listname tells us top index number
 
print "You now have ",$#abc," Children\n";
 
# -------- Handling each element of a list
# ---- use "for" if I need to know the key no.
# ---- use "foreach" if I just want to process content
 
for ($k=0; $k<=$#nextyear; $k++) { # Start ; end condition; step syntax
  print "Child $k will be $nextyear[$k] next year\n";
  }
 
foreach $kiddo (@nextyear) {
  print "We will have a $kiddo y.o. child\n";
  }


We run public Perl Programming courses 4 to 6 times a year, and various advanced Perl courses regularly but a little less often - see here for details.
(written 2009-06-10)

 
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
P208 - Perl - Lists
  [28] Perl for breakfast - (2004-08-25)
  [140] Comparison Chart for Perl programmers - list functions - (2004-12-04)
  [230] Course sizes - beware of marketing statistics - (2005-02-27)
  [240] Conventional restraints removed - (2005-03-09)
  [355] Context in Perl - (2005-06-22)
  [463] Splitting the difference - (2005-10-13)
  [560] The fencepost problem - (2006-01-10)
  [622] Queues and barrel rolls in Perl - (2006-02-24)
  [762] Huge data files - what happened earlier? - (2006-06-15)
  [773] Breaking bread - (2006-06-22)
  [928] C++ and Perl - why did they do it THAT way? - (2006-11-16)
  [968] Perl - a list or a hash? - (2006-12-06)
  [1304] Last elements in a Perl or Python list - (2007-08-16)
  [1316] Filtering and altering Perl lists with grep and map - (2007-08-23)
  [1703] Perl ... adding to a list - end, middle, start - (2008-07-09)
  [1828] Perl - map to process every member of a list (array) - (2008-10-09)
  [1917] Out of memory during array extend - Perl - (2008-12-02)
  [1918] Perl Socket Programming Examples - (2008-12-02)
  [2067] Perl - lists do so much more than arrays - (2009-03-05)
  [2295] The dog is not in trouble - (2009-07-17)
  [2484] Finding text and what surrounds it - contextual grep - (2009-10-30)
  [2813] Iterating over a Perl list and changing all items - (2010-06-15)
  [2833] Fresh Perl Teaching Examples - part 2 of 3 - (2010-06-27)
  [2996] Copying - duplicating data, or just adding a name? Perl and Python compared - (2010-10-12)
  [3400] $ is atomic and % and @ are molecular - Perl - (2011-08-20)
  [3548] Dark mornings, dog update, and Python and Lua courses before Christmas - (2011-12-10)
  [3669] Stepping through a list (or an array) in reverse order - (2012-03-23)
  [3870] Writing more maintainable Perl - naming fields from your data records - (2012-09-25)
  [3906] Taking the lead, not the dog, for a walk. - (2012-10-28)
  [3939] Lots of ways of doing the same thing in Perl - list iteration - (2012-12-03)
  [4609] Mapping an array / list without a loop - how to do it in Perl 6 - (2016-01-03)


Back to
How important is a front page ranking on a search engine?
Previous and next
or
Horse's mouth home
Forward to
Learning PHP, Ruby, Lua and Python - upcoming courses
Some other Articles
Running a piece of code is like drinking a pint of beer
Do not re-invent the wheel - use a Perl module
Where do I start when writing a program?
Learning PHP, Ruby, Lua and Python - upcoming courses
Revision / Summary of lists - Perl
How important is a front page ranking on a search engine?
Trowbridge - a missed opportunity? Melksham - into the breach?
CSS Style Diagrams - working out where attributes come from
A (biased?) comparison of PHP courses in the UK
Adding a newsfeed for your users to a multipage PHP application
4759 posts, page by page
Link to page ... 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96 at 50 posts per page


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.

Link to Ezine home page (for reading).
Link to Blogging home page (to add comments).

You can Add a comment or ranking to this page

© WELL HOUSE CONSULTANTS LTD., 2024: 48 Spa Road • Melksham, Wiltshire • United Kingdom • SN12 7NY
PH: 01144 1225 708225 • EMAIL: info@wellho.net • WEB: http://www.wellho.net • SKYPE: wellho

PAGE: http://www.wellho.net/mouth/2226_Rev ... -Perl.html • PAGE BUILT: Sun Oct 11 16:07:41 2020 • BUILD SYSTEM: JelliaJamb