merge & write two jsonl (json lines) files into a new jsonl file in python3.6

Hello I have two jsonl files like so:

one.jsonl

{"name": "one", "description": "testDescription...", "comment": "1"}
{"name": "two", "description": "testDescription2...", "comment": "2"}

second.jsonl

{"name": "eleven", "description": "testDescription11...", "comment": "11"}
{"name": "twelve", "description": "testDescription12...", "comment": "12"}
{"name": "thirteen", "description": "testDescription13...", "comment": "13"}

And my goal is to write a new jsonl file (with encoding preserved) name merged_file.jsonl which will look like this:

{"name": "one", "description": "testDescription...", "comment": "1"}
{"name": "two", "description": "testDescription2...", "comment": "2"}
{"name": "eleven", "description": "testDescription11...", "comment": "11"}
{"name": "twelve", "description": "testDescription12...", "comment": "12"}
{"name": "thirteen", "description": "testDescription13...", "comment": "13"}

My approach is like this:

import json
import glob

result = []
for f in glob.glob("folder_with_all_jsonl/*.jsonl"):
    with open(f, 'r', encoding='utf-8-sig') as infile:
        try:
            result.append(extract_json(infile)) #tried json.loads(infile) too
        except ValueError:
            print(f)

#write the file in BOM TO preserve the emojis and special characters
with open('merged_file.jsonl','w', encoding= 'utf-8-sig') as outfile:
    json.dump(result, outfile)

However I am met with this error: TypeError: Object of type generator is not JSON serializable I will apprecite your hint/help in any ways. Thank you! I have looked other SO repos, they are all writing normal json files, which should work in my case too, but its keep failing.

Reading single file like this works:

data_json = io.open('one.jsonl', mode='r', encoding='utf-8-sig') # Opens in the JSONL file
data_python = extract_json(data_json)
for line in data_python:
    print(line)

####outputs####
#{'name': 'one', 'description': 'testDescription...', 'comment': '1'}
#{'name': 'two', 'description': 'testDescription2...', 'comment': '2'}

Answer

It is possible that extract_json returns a generator instead of a list/dict which is json serializable
since it is jsonl, which means each line is a valid json
so you just need to tweak your existing code a little bit.

import json
import glob

result = []
for f in glob.glob("folder_with_all_jsonl/*.jsonl"):
    with open(f, 'r', encoding='utf-8-sig') as infile:
        for line in infile.readlines():
            try:
                result.append(json.loads(line)) # read each line of the file
            except ValueError:
                print(f)

# This would output jsonl
with open('merged_file.jsonl','w', encoding= 'utf-8-sig') as outfile:
    #json.dump(result, outfile)
    #write each line as a json
    outfile.write("n".join(map(json.dumps, result)))

Now that I think about it you didn’t even have to load it using json, except it will help you sanitize any badly formatted JSON lines is all

you could collect all the lines in one shot like this

outfile = open('merged_file.jsonl','w', encoding= 'utf-8-sig')
for f in glob.glob("folder_with_all_jsonl/*.jsonl"):
    with open(f, 'r', encoding='utf-8-sig') as infile:
        for line in infile.readlines():
            outfile.write(line)
outfile.close()