Sets a key/value pair on a map.

Places an map on the stack.

This function modifies map to include a new key-value pair.

If the key already exists, it will be overwritten with the new value.

If the key does not already exist, it will be added to the map.

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

{ “name”: “alpha”,

     "colour": "orange",
     "style": "plain" }
      

…then the command 'colour' 'blue' MAPSET will change the 'colour' element from orange to blue.

MAPFILTER