preg_grep() returns the array consisting of
the elements of the input
array that match
the given pattern
.
flags
can be the following flag:
If this flag is passed, preg_grep() returns the
elements of the input array that do not match
the given pattern
.
This flag is available since PHP 4.2.0.
Since PHP 4.0.4, the results returned by preg_grep() are indexed using the keys from the input array. If this behavior is undesirable, use array_values() on the array returned by preg_grep() to reindex the values.