Xbase++

Get the Index of a JSON Member

See more JSON Examples

This example demonstrates how to get the index of a given member by name.

{
  "name": "donut",
  "image":
    {
    "fname": "donut.jpg",
    "w": 200,
    "h": 200
    },
  "thumbnail":
    {
    "fname": "donutThumb.jpg",
    "w": 32,
    "h": 32
    }
}

Xbase++

LOCAL nSuccess
LOCAL oJson
LOCAL cJsonStr
LOCAL nNameIndex
LOCAL nThumbIndex
LOCAL nFnameIndex
LOCAL oImageObj

nSuccess := 0

oJson := CreateObject("Chilkat.JsonObject")

//  This is the above JSON with whitespace chars removed (SPACE, TAB, CR, and LF chars).
//  The presence of whitespace chars for pretty-printing makes no difference to the Load
//  method. 
cJsonStr := '{"name": "donut","image":{"fname": "donut.jpg","w": 200,"h": 200},"thumbnail":{"fname": "donutThumb.jpg","w": 32,"h": 32}}'

nSuccess := oJson:Load(cJsonStr)
IF (nSuccess == 0)
    ? oJson:LastErrorText
    oJson:destroy()
    RETURN
ENDIF

//  The top-level JSON object has three members: name, image, and thumbnail.
nNameIndex := oJson:IndexOf("name")
//  The index of the "name" member is 0.
? "nameIndex = " + Str(nNameIndex)

nThumbIndex := oJson:IndexOf("thumbnail")
//  The index of the "thumbnail" member is 2.
? "thumbIndex = " + Str(nThumbIndex)

//  The "fname" member is NOT a direct member of the top-level JSON object.
//  It is a member of a nested object.  If we try to get the index of this
//  member using the top-level JSON object, it is not found (and returns -1).
nFnameIndex := oJson:IndexOf("fname")
//  The fnameIndex is -1 (not found).  This is correct.
? "fnameIndex = " + Str(nFnameIndex)

//  Get the "image" object.
oImageObj := CreateObject("Chilkat.JsonObject")
oJson:ObjectOf2("image", oImageObj)

//  Now we can get the index of the "fname" object, because it is a direct
//  member of the "image" object:
nFnameIndex := oImageObj:IndexOf("fname")
? "fnameIndex = " + Str(nFnameIndex)

oJson:destroy()
oImageObj:destroy()