PHP - Arrays

PHP module H106

Arrays

Exercises, examples and other material relating to training module H106. This topic is presented on public courses Learning to program in PHP, PHP Programming, Beginning PHP - weekend course / hobby / club / leisure users

Arrays are PHP variables into which you can save more than one value. You can then use a loop to process each individual value, you can refer to individual values by using a special syntax, or you can perform operations on the array as a whole.

Articles and tips on this subject		updated
4068	Arrays in PHP - contain different and even mixed data types PHP's arrays can be keyed by both value and by string... and on this week's PHP course we've covered both. An indexed array (not really an array - rather akin to a list in Perl or Python) starts at index element number 0 and works up from there. Each array member may contain a different type of data, ...	2013-05-04
4072	Splitting the difference with PHP There are lots of ways of splitting a string into pieces - you can do it character by characters, at a specific character, and word by word. PHP provides functions for splitting strings in these ways - and more - into arrays of shorter strings. To split a string into a list of single character strings: $first ...	2013-04-27
1451	More PHP sample and demonstration programs It's amazing how many little (and not so little) new programs and demonstrations I write - here are some from the last couple of days: • The Melksham / Bowerhill Christmas Quiz, 2007. Ten questions, work out the answers, click on a link at the bottom the page and it will be refreshed to tell you ...	2013-01-02
3534	Learning to program in PHP - Regular Expression and Associative Array examples There's a lot to learn on a week-long PHP course - especially if you're new to programming. And delegates need practice during and after the course with some relatively straightforward (but rewarding) real applications. One of the things that we do ourselves is to analyse server log files - allowing ...	2011-12-03
3379	Sorting data the way YOU want it sorted Pieces of program code ... subroutines, functions, macros, procedures, user commands, methods ... are stored with a name, and within many programming languages are actually stored in the same memory area and under the same structure as other named values - variables. This means that you can pass in ...	2011-08-05
3004	Increment operators for counting - Perl, PHP, C and others Look at this Perl statement: $counter = $counter + 1; "Take the value in $counter, add 1 to it, and put it back in $counter". It's a common programing requirement - indeed, so common that you can write it in a shorter form in many languages: $counter += 1; "Add one to the value ...	2010-10-20
2915	Looking up a value by key - associative arrays / Hashes / Dictionaries In any substantial programming task, you'll want to store a whole series of values in some sort of table, so that you can process / reprocess / handle each of the elements in turn - and to do that, you'll use a variable construct that's called an "array", or a "list", a "tuple" or a "vector". (The exact ...	2010-08-20
2920	Sorting - naturally, or into a different order There's a natural sort order for many things - for numbers, it's ascending, for words it's a dictionary order, for names it's by surname. But sometimes you want to sort a list of things different, or there's no provided way within a programming language to apply the natural sort to your type of thing. In ...	2010-08-20
1199	Testing for one of a list of values. Question [PHP] When you have a string of conditions in an 'if' clause and one side of the conditional expression is the same in each condition, is there any shortcut to avoid writing out every expression in full. For examples, rather than writing if(($name!='Lisa')&&($name!='Leah')&&($name!='Christine')) ...	2010-05-16
2274	PHP preg functions - examples and comparision preg_match('%CheckUpdateTime(.?)Main content end%s',$stuff,$gotten); preg_match_all('%(<td class="destination">.?)</tr>%s',$gotten[1],$service); foreach ($service[1] as $train) { $teapot = preg_split('%</td>%',$train); foreach ($teapot as $element) { $el ...	2009-07-10
2215	If nothing, make it nothing. Here's a peculiar PHP statement I wrote this morning: if ($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 ...	2009-06-03
1116	PHP adding arrays / summing arrays A question from my mailbox, answered in relation to our hotel. "I have a number of arrays in PHP and I want to add the elements of the arrays together". "There doesn't appear to be an array_sum function". So in other words, my correspondent may have room occupancy data such as: $bed1 = array(2,2,2,0,2,0,0); $bed2 ...	2009-05-04
1614	When an array is not an array An array, I was taught, is a sequential series of memory locations in which values of some type are stored. In an array, each of the memory locations is the same size (number of bytes). And so, as I was taught, arrays can be used very efficiently using pointer arithmetic, BUT they need to: a) Be defined ...	2008-04-19
832	Displaying data at 5 items per line on a web page If you want to display a list of items in (say) 5 columns on a web page, use a table. A loop in PHP will let you generate all the table cells very easily, then add in a little extra code to deal with: a) The very first cell (you need to open table and row) b) Every fifth cell (you need ...	2006-08-14
773	Breaking bread How can I take ONE thing, discard some of it, and end up with MANY things all of the same type as the original? Surely that doesn't make sense does it? I could take a packet of half a dozen rolls from the supermarket, made (as they often are in the UK) as a single piece of bread with narrow "tear" ...	2006-06-22
603	PHP - setting sort order with an associative array I was updating one of our web site scripts a few hours back, and I wanted to sort the rows of an HTML table generated by the PHP from a directory listing. Problem was that I was making the table up using concatanation (.=) operators in a single string. First solution - put all the table rows into ...	2006-06-05

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Examples from our training material

5pl.php	Display a list in columns
a1.php	Setting up an array, looking at individual elements
a2.php	Array - dealing with missing elements and finding keys
a3.php	Array_walk example. Also the difference between null and empty
arrarr.php	Summing arrays in PHP
arrx.php	Ways of passing through an array
assoc.php	Associative array - sorting and traversing
fullmenu.php	Ordering system from menu file
herbert.php	finding a value from a list of ranges
menu.txt	Menu for fullmenu.php example
nb.html	Speed networking - generate a page for an attendee
nbm.html	Speed networking - seating matrix generator
patrick.php	User defined sort
pflog.php	Most viewed pictures (Mk 1)
pflog2.php	Where are scripts loaded from (2)
rubys.php	read a file into an array and display selected items
simgrep.php	read a file into an array and display selected items
skills.php	A Small search tool
ts.php	Lengthen or shorten an array
walter.php	regular and associative arrays

Background information

This module is available under an Open Training Notes License for free download from http://www.training-notes.co.uk.

Topics covered in this module

Array manipulation.
Array functionality.
Creating Arrays.
Manipulating arrays.

Complete learning

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