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For 2021 - online Python 3 training - see ((here)).

Our plans were to retire in summer 2020 and see the world, but Coronavirus has lead us into a lot of lockdown programming in Python 3 and PHP 7.
We can now offer tailored online training - small groups, real tutors - works really well for groups of 4 to 14 delegates. Anywhere in the world; course language English.

Please ask about private 'maintenance' training for Python 2, Tcl, Perl, PHP, Lua, etc.
If nothing, make it nothing.

Here's a peculiar PHP statement I wrote this morning:
  if ($aindex[$chk] == "") $aindex[$chk] = "";

What was I doing? I am actually checking to see whether there's anything in an array element and if there isn't (which could be because it's empty or because it doesn't yet exist), then it should be created if necessary and made to contain an empty string. In PHP, = = tests whether two expressions have an equal values, but = = = tests whether they are of the same type and with equal value.

The important aspect of the assignment that's made above is that it ensures that the array ends up with an element who's key is the contents of $chk, so that later on in my code I can go though all of the items using array_keys even for $chk values for which there is no data.
(written 2009-06-02, updated 2009-06-03)

 
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
H999 - Additional PHP Material
  [54] PHP and natural sorting - (2004-09-19)
  [239] What and why for the epoch - (2005-03-08)
  [320] Ordnance Survey - using a 'Get a map' - (2005-05-22)
  [322] More maps - (2005-05-23)
  [337] the array returned by preg_match_all - (2005-06-06)
  [372] Time calculation in PHP - (2005-07-08)
  [468] Stand alone PHP programs - (2005-10-18)
  [483] Double Dollars in PHP - (2005-11-02)
  [493] Running a Perl script within a PHP page - (2005-11-12)
  [563] Merging pictures using PHP and GD - (2006-01-13)
  [603] PHP - setting sort order with an associative array - (2006-02-13)
  [665] PHP Image viewing application - (2006-04-01)
  [687] Presentation, Business and Persistence layers in Perl and PHP - (2006-04-17)
  [789] Hot answers in PHP - (2006-07-02)
  [806] Check your user is human. Have him retype a word in a graphic - (2006-07-17)
  [822] PHP - a team member leaves - (2006-08-04)
  [839] Reporting on the 10 largest files or 10 top scores - (2006-08-20)
  [917] Syntax checking in PHP - (2006-11-07)
  [937] Display an image from a MySQL database in a web page via PHP - (2006-11-22)
  [1010] Dates, times, clickable diarys in PHP - (2006-12-28)
  [1020] Parallel processing in PHP - (2007-01-03)
  [1053] Sorting people by name in PHP - (2007-01-26)
  [1104] Drawing dynamic graphs in PHP - (2007-03-09)
  [1194] Drawing hands on a clock face - PHP - (2007-05-19)
  [1270] PHP Standalone - keyboard to screen - (2007-07-18)
  [1389] Controlling and labelling Google maps via PHP - (2007-10-13)
  [1390] Converting from postal address to latitude / longitude - (2007-10-13)
  [1391] Ordnance Survey Grid Reference to Latitude / Longitude - (2007-10-14)
  [1451] More PHP sample and demonstration programs - (2007-12-01)
  [1485] Copyright and theft of images, bandwidth and members. - (2007-12-26)
  [1505] Script to present commonly used images - PHP - (2008-01-13)
  [1519] Flipping images on your web page - (2008-01-26)
  [1623] PHP Techniques - a workshop - (2008-04-26)
  [2073] Extra PHP Examples - (2009-03-09)
  [2684] Exception handling in PHP - (2010-03-18)
  [3118] Arrays of arrays - or 2D arrays. How to program tables. - (2011-01-02)
  [3210] Catchable fatal error in PHP ... How to catch, and alternative solutions such as JSON - (2011-03-22)
  [4655] Image indexer / thumbnail display scripts in PHP - (2016-02-25)

H106 - PHP - Arrays
  [409] Functions and commands with dangerous names - (2005-08-11)
  [773] Breaking bread - (2006-06-22)
  [832] Displaying data at 5 items per line on a web page - (2006-08-14)
  [1116] PHP adding arrays / summing arrays - (2007-03-23)
  [1199] Testing for one of a list of values. - (2007-05-22)
  [1614] When an array is not an array - (2008-04-17)
  [2274] PHP preg functions - examples and comparision - (2009-07-08)
  [2915] Looking up a value by key - associative arrays / Hashes / Dictionaries - (2010-08-11)
  [2920] Sorting - naturally, or into a different order - (2010-08-14)
  [3004] Increment operators for counting - Perl, PHP, C and others - (2010-10-18)
  [3379] Sorting data the way YOU want it sorted - (2011-08-05)
  [3534] Learning to program in PHP - Regular Expression and Associative Array examples - (2011-12-01)
  [4068] Arrays in PHP - contain different and even mixed data types - (2013-04-24)
  [4072] Splitting the difference with PHP - (2013-04-27)
  [4244] Disambiguation - PHP List - (2014-03-07)

H103 - PHP - Variables, Operators and Expressions
  [748] Getting rid of variables after you have finished with them - (2006-06-06)
  [3278] Do I need to initialise variables - programming in C, C++, Perl, PHP, Python, Ruby or Java. - (2011-05-05)
  [3916] PHP variables - dynamically typed. What does that mean? - (2012-11-08)
  [3917] BODMAS - the order a computer evaluates arithmetic expressions - (2012-11-09)
  [4324] Learning to program - variables and constants - (2014-11-22)
  [4642] A small teaching program - demonstration of principles only - (2016-02-08)


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Configuring httpd, or Tomcat, to run CGI scripts in Perl
Multiple web applications under Tomcat - what are the options?
Enjoying the summer weather
Past Delegate Offer - Summer Holiday / Weekend Break
If nothing, make it nothing.
Global Index to help you find resources
Keyboard reading in Perl - character by character not line by line
Dripping taps, Java threads and the single thread model
Tcl/Tk - why does the canvas widget use a display list?
MySQL server replication
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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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