From the NannyMUD documentation
2000-12-14
NAME
filter_array - Filter an array.SYNTAX
mixed *filter_array(mixed *arr, string fun, object ob, mixed extra);DESCRIPTION
Returns an array holding the items of 'arr' filtered through ob->fun(). The function 'fun' in 'ob' is called for each element in 'arr' with that element as parameter. A second parameter 'extra' is sent in each call if given. If ob->fun(arr[.index.], extra) returns 1 the element is included in the returned array.