B4X

Check if Integer Exists at JSON Path

Demonstrates how to get an integer value at a JSON path, and how to check to see if it exists. B4X

Dim success As Boolean = False

Dim json As ChilkatJsonObject
json.Initialize

'  First build simple JSON..
json.UpdateInt("test.abc", 100)

json.EmitCompact = False
Log(json.Emit)

'  This is our JSON:
'  {
'    "test": {
'      "abc": 100,
'    }
'  }

Dim path As String = "test.notHere"

'  The call to IntOf will return 0, because it's not present.
'  But how do we know if it really was present, and the value was truly 0?
Dim val As Int = json.IntOf(path)
Log("val = " & val)

'  We cannot use LastMethodSuccess because LastMethodSuccess only applies
'  to methods that:
'  - return a string
'  - return a new Chilkat object, binary bytes, or a date/time.
'  - returns a boolean status where True = success and False = failed.
'  - returns an integer where failure is defined by a return value less than zero.
'  The IntOf method fits none of these requirements, and therefore the LastMethodSuccess 
'  is not a valid indicator..
Dim wasFound As Boolean = json.LastMethodSuccess
Log("wasFound = " & wasFound & " (not a valid indicator)")

'  Instead, if the returned value is 0, we can double-check to see if the member was truly there..
If val = 0 Then
    wasFound = json.HasMember(path)
    Log("wasFound = " & wasFound)
    If wasFound = True Then
        Log("The value was present and is 0.")
    Else
        Log("no member is present at test.notHere")
    End If

Else
    Log("val = " & val)
End If


'  Alternatively, you could check to see if the member exists beforehand..
If json.HasMember(path) = True Then
    Log("val = " & json.IntOf(path))
Else
    Log("no member at " & path)
End If