I have spent a long time looking through the forums, but just cannot get this to work.
I have a multidimensional, assoctaive array (in a class). It is declared as:
protected $ISSNLookup = array();
In a function, I say (to populate the array from another data source):
foreach($this->keys as $k) {
$issn = $this->getISSN($k);
if($issn != '') { // This publication has an ISSN
if(array_key_exists($issn, $this->ISSNLookup)) {
$this->ISSNLookup[$issn]['number']++;
}
else {
$addItem = array( 'journal' => $this->getJournal($k), 'number' => 1);
$this->ISSNLookup[$issn] = $addItem;
} // else, key not on $ISSNLookup
} // if $issn != ''
} // foreach
If I then display the array contents, using:
foreach($this->ISSNLookup as $key => $value) {
echo $key . ' (' . $value['journal'] . '): ' . $value['number'] . '</br>';
}
... all looks good. That is (this is just a sample):
0924-669X (Applied Intelligence): 3
1943-068X (IEEE Transactions on Computational Intelligence and AI in Games): 6
1000-9000 (Journal of Computer Science and Technology): 1
0377-2217 (European Journal of Operational Research): 8
0020-7721 (International Journal of Systems Science): 1
1619-4500 (4OR - A Quarterly Journal of Operations Research): 2
0160-5682 (Journal of the Operational Research Society): 11
If I now sort, using
usort($this->ISSNLookup, array($this, 'ISSNLookupJournalNameSort'));
with the function (to compare the values):
function ISSNLookupJournalNameSort($a, $b) {
return strcmp($a['journal'], $b['journal']);
}
and display again (using the same code as above), I get:
0 (4OR - A Quarterly Journal of Operations Research): 2
1 (Advances in Econometrics): 1
2 (Annals of Operations Research): 3
3 (Applied Intelligence): 3
4 (Applied Soft Computing): 3
5 (Artificial Life): 1
The sort has worked (i.e. the names are sorted - but what has happened to the 9-char ID? It seems to have reverted to a counter
Any help appreciated.