Sorting contents of an array before display

Chris_96_WS6

I have a table of users, each user has a course history that looks like this:

;0001,Econ 101, Economics Dept,2007-12-31;0013,Intro to Psychology,Education & Behavior Dept,2007-07-06

The back end user can go in and view this for each user, or print a PDF transcript.

I am using explode to break the string on the semicolons, each resulting string being then split and printed using list($ClassID, $Title, $Dept, $Date).

The output looks like this:

0001 -- Econ 101 -- Economics Dept -- 2007-12-31
0013 -- Intro to Psychology -- Education & Behavior Dept -- 2007-12-31

Now, what I'd prefer to do is rather than list them all in series, is sort them by the third variable, $Dept, and then display like this:

Economics Dept
Econ 101, 2007-12-31

Education & Behavior Dept
Intro to Psychology, 2007-12-31

So I'm looking for help on how to read the array, then sort before outputting.

matto

first read it into an array:
start as you did before: "I am using explode to break the string on the semicolons, each resulting string being then split and" - now write it into a 2-dimensional array: $data[$i][$j] = (one of the elements of the inner split)

now sort the 2-dim array. look at the usort function in the manual!
you can just do

usort($data, 'data_cmp');

if you write a comparator function named "data_cmp" like demonstrated in the PHP usort manual.

an example I just coded today:
I have a data structure $data = array(array('bla', 123, 234), ...)
I want to try to sort the elements by their sub-element #1 (eg 123),
but in case they are the same I want to sort them by #2 (eg 234).

the comparator function looks like this:

/**
 * comparator function used by sva_class_ranking
 *
 * @param array $a
 * @param array $b
 * @return integer
 */
function sva_freq_cmp($a, $b)
{
	$ret = 0;

if($a[1] == $b[1])
{
	if($a[2] == $b[2])
		$ret = 0;
	else
		$ret = ($a[2] < $b[2] ? -1 : 1);
}
else
{
	$ret = ($a[1] < $b[1] ? 1 : -1);
}

return $ret;
}