Write multiple JSON lines to JSON file

Question

I have a code that needs to read a JSON file with multiple lines, i.e:

{"c1-line1": "value", "c2-line1": "value"}
{"c1-line2": "value", "c2-line2": "value"}...

and, after change the keys values (already working), I need to write a new json file with these multiple lines, i.e:

{"newc1-line1": "value", "newc2-line1": "value"}
{"newc1-line2": "value", "newc2-line2": "value"}...

My problem is that my code are just writing the last value readed:

{"newc1-line2": "value", "newc2-line2": "value"}

My code:

def main():
   ... # changeKeyValueCode
   writeFile(data)
 
def writeFile(data):
   with open('new_file.json', 'w') as f:
       json.dump(data, f)

I already tried with json.dumps and just f.write('') or f.write('\n')

I know that data in writeFile() is correctly with each line value.

How can I resolve this, please?

open('new_file.json', 'w') opens file for writing, if you call writeFile in a loop it will overwrite previous content, try calling open with a flag, to append, so it will look like this: open('new_file.json', 'a'). Anyway, opening file in a loop isn't that good, if this is the case. — Monsieur Merso
– Monsieur Merso, Commented Mar 25, 2022 at 12:55

Nerdy Ayubi · Accepted Answer · 2022-08-21 21:07:09Z

2

def main():
   ... # changeKeyValueCode
   writeFile(data)
 
def writeFile(data):
   with open('new_file.json', 'a') as f:
       json.dump(data, f)

with open('new_file.json', 'a')

open file with (a), it will search the file if found append data to the end, else it will create empty file and then append data.

answered Aug 21, 2022 at 21:07

Nerdy Ayubi

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