DataFlex

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
    }
}

DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoJson
    String sJsonStr
    Integer iNameIndex
    Integer iThumbIndex
    Integer iFnameIndex
    Variant vImageObj
    Handle hoImageObj
    String sTemp1

    Move False To iSuccess

    Get Create (RefClass(cComChilkatJsonObject)) To hoJson
    If (Not(IsComObjectCreated(hoJson))) Begin
        Send CreateComObject of hoJson
    End

    // 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. 
    Move '{"name": "donut","image":{"fname": "donut.jpg","w": 200,"h": 200},"thumbnail":{"fname": "donutThumb.jpg","w": 32,"h": 32}}' To sJsonStr

    Get ComLoad Of hoJson sJsonStr To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoJson To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // The top-level JSON object has three members: name, image, and thumbnail.
    Get ComIndexOf Of hoJson "name" To iNameIndex
    // The index of the "name" member is 0.
    Showln "nameIndex = " iNameIndex

    Get ComIndexOf Of hoJson "thumbnail" To iThumbIndex
    // The index of the "thumbnail" member is 2.
    Showln "thumbIndex = " iThumbIndex

    // 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).
    Get ComIndexOf Of hoJson "fname" To iFnameIndex
    // The fnameIndex is -1 (not found).  This is correct.
    Showln "fnameIndex = " iFnameIndex

    // Get the "image" object.
    Get Create (RefClass(cComChilkatJsonObject)) To hoImageObj
    If (Not(IsComObjectCreated(hoImageObj))) Begin
        Send CreateComObject of hoImageObj
    End
    Get pvComObject of hoImageObj to vImageObj
    Get ComObjectOf2 Of hoJson "image" vImageObj To iSuccess

    // Now we can get the index of the "fname" object, because it is a direct
    // member of the "image" object:
    Get ComIndexOf Of hoImageObj "fname" To iFnameIndex
    Showln "fnameIndex = " iFnameIndex


End_Procedure