- strtotime: documentation ( source)
<?php
$datesarray = array('2012-10-01', '2012-10-03', '2012-10-05', '2012-10-08', '2012-10-09');
$count = 0;
$result = "Nothing found";
$diff = strtotime('2014-05-07') - strtotime('2014-05-06');
for ($i=2, $c=count($datesarray); $i<$c; ++$i) {
if (strtotime($datesarray[$i-1]) - strtotime($datesarray[$i-2]) == $diff &&
strtotime($datesarray[$i]) - strtotime($datesarray[$i-2]) == $diff * 2) {
$result = "3 Consecutive dates found";
break;
}
}
echo "Result: $result";