How to parse and address a json matrix array in Excel-VBA?

Question

I need to parse JSON text to a JSON object in Excel-VBA. The JSON text includes a matrix/array. Then I need to address it (set a VBA variable to the value).

My code had been working parsing a nested/keyed JSON text with "JsonConverter.parseJSON" method. But I do not know how to address new array object (or technically if the "parse" is working correctly.

Dim jsonResults As String
Dim jsonObj As Dictionary
Set travelDist As Number

Set jsonResults = '{"distances":[[0,97641],[97415,0]],"times":[[0,4189],[4183,0]],"weights":[[0.0,5653.726],[5644.176,0.0]],"info":{"copyrights":["GraphHopper","OpenStreetMap contributors"]}}'

Set jsonObj = JsonConverter.ParseJson(jsonResults) \This worked with the old JSON text keyed value structure.

travelDist = VBA.Val(jsonObj.Item("distances")(1)) \This DOESN'T work. It worked with Keyed Object Values.  The goal is to set travelDist to in this example, 97641.

The current code seems to have a type mismatch.

The goal is to set a VBA variable to 97641. Please let me know how to include required files/definitions etc. if the solution is including additional types or methods.

Answer 1

There's no reason to declare jsonObj as a dictionary and unless Number is a well defined user-defined type of some sort, I don't think declaring travelDist as Number will work. Use Double instead. And always use Option Explicit on the very top.

Also the double quotes in the JSON string need to be escaped somehow. You can either double them:

jsonResults = "{""distances"":[[0,97641],[97415,0]],""times"":[[0,4189],[4183,0]],""weights"":[[0.0,5653.726],[5644.176,0.0]],""info"":{""copyrights"":[""GraphHopper"",""OpenStreetMap contributors""]}}"

or replace them with single quotes:

jsonResults = "{'distances':[[0,97641],[97415,0]],'times':[[0,4189],[4183,0]],'weights':[[0.0,5653.726],[5644.176,0.0]],'info':{'copyrights':['GraphHopper','OpenStreetMap contributors']}}"

or you can just store the string in a cell in one of your worksheets and load it from there:

Dim sht As Worksheet
Set sht = ThisWorkbook.Worksheets("Name of your Worksheet")
Set jsonObj = JsonConverter.ParseJson(sht.Range("A1"))

Visualizing the JSON structure might help you understand it better:

So basically what you need to do is access the 2nd item , of the 1st item , of the distances array/collection, keeping in mind that the 1st item of the distances array is also an array/collection itself.

The way to do this would be the following:

Option Explicit

Sub test()
Dim jsonObj As Object
Dim jsonResults As String
Dim travelDist As Double

jsonResults = "{""distances"":[[0,97641],[97415,0]],""times"":[[0,4189],[4183,0]],""weights"":[[0.0,5653.726],[5644.176,0.0]],""info"":{""copyrights"":[""GraphHopper"",""OpenStreetMap contributors""]}}"
Set jsonObj = JsonConverter.ParseJson(jsonResults)

travelDist = jsonObj("distances")(1)(2)
Debug.Print travelDist 'the result is printed in the immediate window
End Sub

Finally, I assume that since you've used this before, you know you need to add this JSON parser to your project, as well as a reference to Microsoft Scripting Runtime (VBE>Tools>References>...)