How to do arithmetic substraction of same identical key values between 2 json files and print it in output json file - json

Question

I've 2 json files of with identical key fields on both the file. I would like to get your assistance to do arithmetic subtraction of values of same key field between 2 files and present in 3rd output file [ delta of two json files to output json file].
Also 1st and 2nd json files has n of array of indicies so we need to do this in loop to map the difference values in 3rd json output file.
Example:
1st Json file: file1.json
[
{
"name": "Rock",
"pri": 21,
"size": 502173,
"gets": 0,
"searches": 40,
"search_time_ms": 25,
"fetches": 2,
"cache_mem_size": 0,
"cache_size": 0,
"cache_total": 2,
"hits": 0,
"misses": 2,
"index_total": 0,
"index_current": 0,
"merges_total": 0,
"refresh_total": 0
},
{
"name": "Rock:config",
"pri": 21,
"size": 512173,
"gets": 0,
"searches": 40,
"search_time_ms": 25,
"fetches": 2,
"cache_mem_size": 0,
"cache_size": 0,
"cache_total": 2,
"hits": 0,
"misses": 2,
"index_total": 0,
"index_curr": 0,
"merges_tot": 0,
"refresh_tot": 0
}
]
2nd Json file: file1.json:
[
{
"name": "Rock",
"pri": 22,
"size": 602173,
"gets": 0,
"searches": 40,
"search_time_ms": 25,
"fetches": 2,
"cache_mem_size": 0,
"cache_size": 0,
"cache_total": 2,
"hits": 0,
"misses": 2,
"index_total": 0,
"index_current": 0,
"merges_total": 0,
"refresh_total": 0
},
{
"name": "Rock:config",
"pri": 31,
"size": 602173,
"gets": 0,
"searches": 40,
"search_time_ms": 25,
"fetches": 2,
"cache_mem_size": 0,
"cache_size": 0,
"cache_total": 2,
"hits": 0,
"misses": 2,
"index_total": 0,
"index_curr": 0,
"merges_tot": 0,
"refresh_tot": 0
}
]
Output json file: file3.json should look like below.
[
{
"name": "Rock",
"pri": 1,
"size": 100000,
"gets": 0,
"searches": 40,
"search_time_ms": 25,
"fetches": 2,
"cache_mem_size": 0,
"cache_size": 0,
"cache_total": 2,
"hits": 0,
"misses": 2,
"index_total": 0,
"index_current": 0,
"merges_total": 0,
"refresh_total": 0
},
{
"name": "Rock:config",
"pri": 10,
"size": 90000,
"gets": 0,
"searches": 40,
"search_time_ms": 25,
"fetches": 2,
"cache_mem_size": 0,
"cache_size": 0,
"cache_total": 2,
"hits": 0,
"misses": 2,
"index_total": 0,
"index_curr": 0,
"merges_tot": 0,
"refresh_tot": 0
}
]
please help me with the logic

Answer 1

This can be done as simple as u follow the following steps
Read the json object from 2 json files and save them as list of dictionaries
Loop through the list of dicts and perform your required manipulations
Save calculated output dicts to a new list
Write the resultant list to a new json file
the code is as follows,
import json
with open('file1.json') as f:
data1 = json.load(f)
with open('file2.json') as f:
data2 = json.load(f)
data = []
for i,j in zip(data1, data2):
x = {}
for m,n in zip(i.items(), j.items()):
# if m[0] != "name":
if m[0] == "pri" or m[0] == "size":
x[m[0]] = int(j[m[0]]) - int(i[m[0]])
else:
x[m[0]] = i[m[0]]
data.append(x)
with open('file3.json', 'w') as o:
json.dump(data, o)