How to check if a string is a valid JSON in python

Question

I have a python script providing command line / output in console on remote linux. I have another script which is reading this output on local machine. Output is in below format:

ABC: NEG
BCD: NEG
FGH: POS
{aa:bb:cc:dd:ee{"value":"30","type":"Tip 3","targetModule":"Target 3","configurationGroup":null,"name":"Configuration Deneme 3","description":null,"identity":"Configuration Deneme 3","version":0,"systemId":3,"active":true}}

notice last line is in json format, now I want to check which line is in json format of the output. I tried

if "value" in line:
    json.loads(line)

it is not reading and even

json.dumps(line)

not giving output ?

Answer 1

You can use try except clause to check if a string is actually json:

import json
line = '<what you think is json>'
try:
    json_line = json.loads(line)
except ValueError:
    print("not a json")

In your above code the last line is not a valid JSON. You can use this tool JSONLint to verify if your JSON is a valid JSON.