PureBasic

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
    }
}

PureBasic

IncludeFile "CkJsonObject.pb"

Procedure ChilkatExample()

    success.i = 0

    json.i = CkJsonObject::ckCreate()
    If json.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; 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. 
    jsonStr.s = "{" + Chr(34) + "name" + Chr(34) + ": " + Chr(34) + "donut" + Chr(34) + "," + Chr(34) + "image" + Chr(34) + ":{" + Chr(34) + "fname" + Chr(34) + ": " + Chr(34) + "donut.jpg" + Chr(34) + "," + Chr(34) + "w" + Chr(34) + ": 200," + Chr(34) + "h" + Chr(34) + ": 200}," + Chr(34) + "thumbnail" + Chr(34) + ":{" + Chr(34) + "fname" + Chr(34) + ": " + Chr(34) + "donutThumb.jpg" + Chr(34) + "," + Chr(34) + "w" + Chr(34) + ": 32," + Chr(34) + "h" + Chr(34) + ": 32}}"

    success = CkJsonObject::ckLoad(json,jsonStr)
    If success = 0
        Debug CkJsonObject::ckLastErrorText(json)
        CkJsonObject::ckDispose(json)
        ProcedureReturn
    EndIf

    ; The top-level JSON object has three members: name, image, and thumbnail.
    nameIndex.i = CkJsonObject::ckIndexOf(json,"name")
    ; The index of the "name" member is 0.
    Debug "nameIndex = " + Str(nameIndex)

    thumbIndex.i = CkJsonObject::ckIndexOf(json,"thumbnail")
    ; The index of the "thumbnail" member is 2.
    Debug "thumbIndex = " + Str(thumbIndex)

    ; 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).
    fnameIndex.i = CkJsonObject::ckIndexOf(json,"fname")
    ; The fnameIndex is -1 (not found).  This is correct.
    Debug "fnameIndex = " + Str(fnameIndex)

    ; Get the "image" object.
    imageObj.i = CkJsonObject::ckCreate()
    If imageObj.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkJsonObject::ckObjectOf2(json,"image",imageObj)

    ; Now we can get the index of the "fname" object, because it is a direct
    ; member of the "image" object:
    fnameIndex = CkJsonObject::ckIndexOf(imageObj,"fname")
    Debug "fnameIndex = " + Str(fnameIndex)


    CkJsonObject::ckDispose(json)
    CkJsonObject::ckDispose(imageObj)


    ProcedureReturn
EndProcedure