exists
The exists
method checks whether a specified path exists in the JSON value.
Syntax
exists( pathElements )
Arguments
Argument | Description |
---|---|
pathElements
|
(json_path_string_or_integer) The path to check. Specify one or more path elements, which might be object attribute names (strings) or array indexes (integers). |
Returns
(Boolean) Returns true
if the path exists, false
otherwise.
Example
Consider the following JSON:
{ "product": "IDOL", "component": "CFS", "version": { "major": 11, "minor": 3 }, "ports": [ { "type": "ACI", "number": 7000 }, { "type": "Service", "number": 17000 } ] }
If this JSON is represented by a LuaJsonValue
object named myJsonValue
, you could use the exists
method as follows:
print (myJsonValue:exists("ports",0,"type")) -- true (LuaJsonArrays are zero-indexed) print (myJsonValue:exists("ports",2,"type")) -- false (LuaJsonArrays are zero-indexed, and there is no third value) print (myJsonValue:exists("version", "major")) -- true