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Map Elements

Map Elements​

Format​

map [ key ]

Description​

After you specify that a variable is a map, by using the Map statement, you can set and retrieve values from the map using square braces containing the key.

Keys should be string values/expressions. If you use an integer or a float as the key, it will be converted to a string. Keys are case-sensitive: "Ann" and "ann" are two different keys.

Reading a key that is not in the map is error 126, "Map key has not been assigned a value", the same as reading a variable that was never assigned (how it is reported follows the "Runtime handling of unassigned variables" preference). To ask whether a key is there, use in: key in map is true when the map has that key and false when it has not, and never stops the program. Assigned gives the same answer.

Example​

map ages
ages["Ann"] = 12
ages["Cy"] = 9
if "Bob" in ages then
    print "Bob is " + ages["Bob"]
else
    print "Bob is not in the map"
end if
print "Ann" in ages

displays

Bob is not in the map
1

Before BASIC256 2.3.2, in and assigned also raised error 126 for a missing key.

See Also​

ArrayBase, ArrayLength, Assigned, Dim, Fill, Map, Redim, TypeOf, Unassign, VariableWatch