exists

The exists method checks whether a specified path exists in the JSON object.

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 an object named myJsonObject, you could use the exists method as follows:

print (myJsonObject:exists("ports",0,"type"))
-- true (LuaJsonArrays are zero-indexed)

print (myJsonObject:exists("ports",2,"type"))
-- false (LuaJsonArrays are zero-indexed, and there is no third value)

print (myJsonObject:exists("version", "major"))
-- true

See Also


_HP_HTML5_bannerTitle.htm