From the NannyMUD documentation

LAST CHANGE

2000-12-14

FUNCTION

NAME
        filter_mapping - Filter a mapping through a function.


SYNTAX
	mapping filter_mapping(mapping m, string fun, object ob, mixed extra);

DESCRIPTION
	This function calls ob->fun once for each value in the mappping,
	just like map_mapping, but instead of building a mapping of the
	results, it returns a mapping consisting of those values and indices
	for which the function ob->fun returns true. The optional extra
	argument is sent to the function as a second argument for each
	call if present.


EXAMPLE
	The code:

	int foo(int x,int y) { return x<=y; }
	filter_mapping((["foo":1,"bar":5,"gazonk":6]),"foo",this_object(),5);

	Would result in: (["foo":1,"bar":5])


SEE ALSO
        filter_array in efun/type_related/filter_array


SEE ALSO
        map_mapping in efun/type_related/map_mapping