Compare 2 Json files and display the difference of second file

Question

These are the two json files i have JSON1.json

{

  "name": "HOSTNAME1",

  "chef_environment": "non_prod",

  "run_list": [

    "role[MyOrg-non_prod]",

    "role[rhel7-latest]",

    "role[middleware-nonprod-all]",

    "role[MyApp-middleware_corebase_prod]",

    "role[MyApp_envs-test]",

    "role[MyApp_envs-dev]",

    "role[MyApp_nfs_mount]",

    "role[MyApp_access-dev]",

    "role[MyOrg-client-wrapper]"

  ]

}

JSON2.json

{

  "name": "HOSTNAME2",

  "chef_environment": "non_prod",

  "run_list": [

    "role[MyOrg-non_prod]",

    "role[rhel7-latest]",

    "role[MyApp_unix_app-dev]",

    "role[MyApp_middleware_corebase_prod]"

  ]

}

These files may or may not be sorted. I need to get the unique values of JSON2 which are not available in JSON1

I have initially tried it using commands like

findstr /vig:JSON1.json JSON2.json  | grep -v name| grep -e MyApp -e MyOrg | tr -d '\n'| sed -e 's:"::g' -e 's: *::g'  -e 's:,$::'

However this dosent work, consider for example In JSON1 i have an entry "role[MyApp_middleware_corebase_prod]",

and in JSON2 "role[MyApp_middleware_corebase_prod]"

Note the difference in comma, although the entry is same and hence not unique, however due to presence of comma this is considered as unique and gives me an undesired output.

If i compare JSON1 vs JSON2 the expected output is role[MyApp_unix_app-dev] as this is ONLY unique to JSON2

And if i compare JSON2 vs JSON1

role[MyApp_envs-test],role[MyApp_envs-dev],role[MyApp_nfs_mount],role[MyApp_access-dev],role[MyOrg-client-wrapper]

check this https://stackoverflow.com/a/45937169/10727144 – Amit Nanaware Jun 27 '19 at 13:34 — Amit Nanaware, Jun 27 '19 at 13:34

score 2 · Accepted Answer · answered Jun 27 '19 at 13:48

2

Set subtraction (difference) is what I think you actually want:

import json


with open('json1.json', 'r') as f:
    json1 = json.load(f) 

with open('json2.json', 'r') as f:
    json2 = json.load(f) 

json2['run_list'] = list(set(json2['run_list']) - set(json1['run_list']))

print(json.dumps(json2, indent=2))

Output:

{
  "name": "HOSTNAME2",
  "chef_environment": "non_prod",
  "run_list": [
    "role[MyApp_unix_app-dev]"
  ]
}

answered Jun 27 '19 at 13:48

Error - Syntactical Remorse

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Great, thanks. However Can we just print the contents of run_list i.e role[MyApp_unix_app-dev] – maverick Jun 28 '19 at 04:43
@baggi `print(json.dumps(json2['run_list'], indent=2))` – Error - Syntactical Remorse Jun 28 '19 at 12:16
@baggi and you don't need to print it using `json.dumps(...)`, I just do that because it looks cleaner with the indent. – Error - Syntactical Remorse Jun 28 '19 at 12:23

score 1 · Answer 2 · answered Jun 27 '19 at 13:40

you can use python set intersection

json1 = {

      "name": "HOSTNAME1",

      "chef_environment": "non_prod",

      "run_list": [

        "role[MyOrg-non_prod]",

        "role[rhel7-latest]",

        "role[middleware-nonprod-all]",

        "role[MyApp-middleware_corebase_prod]",

        "role[MyApp_envs-test]",

        "role[MyApp_envs-dev]",

        "role[MyApp_nfs_mount]",

        "role[MyApp_access-dev]",

        "role[MyOrg-client-wrapper]"

        ]

       }

json2={

          "name": "HOSTNAME2",

          "chef_environment": "non_prod",

          "run_list": [

            "role[MyOrg-non_prod]",

            "role[rhel7-latest]",

            "role[MyApp_unix_app-dev]",

            "role[MyApp_middleware_corebase_prod]"

          ]

        }
set1 = set(json1['run_list'])
set2 = set(json2['run_list'])
set3 = set1.intersection(set2)

Intersection just returns an empty set – maverick Jun 28 '19 at 04:45 — maverick, Jun 28 '19 at 04:45

Compare 2 Json files and display the difference of second file

2 Answers2