Something like this shall do the trick:
$knownIds = array();
foreach( $myArray AS $key=>$item ) {
if( array_key_exists($item['event_id'], $knownIds) === true ) {
unset( $myArray[$key] );
} else {
$knownIds[$item['event_id']] = $key; // value does not matter really here
}
}
$myArray = array_values($myArray);
where $myArray
is your source array.
3
solved Remove From multidimensional array if a value is duplicate [duplicate]