MAPFILTER

Filters a map for specific items.

There are two variants of this function that work differently

Order	Name	Type	Desc
1	original	map	The map to be filtered
2	filterkey	const	The name of the map item to be searched for
3	filtervalue	const	The value of the map item to allow

Order	Name	Type	Desc
1	original	map	The map to be filtered
2	filterkey	map	The filter

Places an map on the stack.

This function filters the map (original).

If using the three-parameter version, any item that does not contain the specified filterkey and filtervalue will be removed.

If using the two-parameter version, any item that does not contain each of the map keys and values found in filterkey will be removed.

For example, if you had the following map in your stack…

 [ { "name": "alpha",
     "colour": "orange",
     "style": "plain" },
    { "name": "beta",
      "colour":"blue",
      "style":"exotic"} ]

…then the command 'colour' 'blue' MAPFILTER will remove 'alpha' from your map, leaving only 'beta'.