How to extract values from json which has multiple hierarchies inside using Python

Question

Below is the json content, how to extract values for "GBL_ACTIVE_CPU" using python.

{
        "test": "00.00.004",
        "Metric Payload": [
            {
                "ClassName": "test",
                "SystemId": "test",
                "uri": "http://test/testmet",
                "MetaData": [
                    {
                        "FieldName": "GBL_ACTIVE_CPU",
                        "DataType": "STRING",
                        "Label": "test",
                        "Unit": "string"
                    }
                ],
                "Instances": [
                    {
                        "InstanceNo": "0",
                        "GBL_ACTIVE_CPU": "4"
                    }
                ]
        ]               
}

I tried below code, but doesn't work. Any help is appreciated:

result = json.loads(jsonoutput)
print(result)
node = result["Metric Payload"]["Instances"]["GBL_ACTIVE_CPU"]
print(node)

I get below error:

TypeError: list indices must be integers or slices, not str

Answer 1

In JSON " Instances " is a list. You are accessing it like a dict. So it have 2 ways on is static other is dynamic.

If you like to use static way:-

result = json.loads(jsonoutput)
print(result)
node = result["Metric Payload"][0]["Instances"][0]["GBL_ACTIVE_CPU"]
print(node)

If you like to use dynamic way:-

result = json.loads(jsonoutput)
print(result)
for metric in result["Metric Payload"]: 
    for inst in metric["Instances"]:
        node = inst["GBL_ACTIVE_CPU"]
        print(node)