Thursday, February 09, 2006

Where's the Monkey - Pointers


<?php
function wheresTheMonkey() {

//A
$months = array();
for ($i=6; $i>=0; $i--) {
$months[$i]["start"] = mktime(0,0,0, date("m")-(1*$i), 1, date("Y"));

}

print_r($months);

//B
foreach ($months as &$month) {
$month["end"] = strtotime("now +1 month", $month["start"]);
}

print_r($months);

//C
foreach ($months as $month) {
printf("%s\t\t%s\n",date("d F y", $month["start"]), $month["start"]);

}
}

print '<pre>';
wheresTheMonkey();
print '</pre>';

?>


This caused me a headache today - monkey business everywhere. If you don't get the gotcha; $month is still a pointer / reference to an array element in $months, so doing another foreach assigns a new value to $months[0] when you set $month!

It's too easy to forget in PHP...
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