CODEWITHSUNDEEP
python-3.x
Gary Glasspool
Gary Glasspool

Reputation: 87

How to replace None value with "None" string value

I have a text file that I am trying to write to a JSON file. Some of the values are returned as None, True or False. I need to replace None with "None" (string), True with "True" and False with "False"

I tried adding the line

data=data.replace(None,"None")

However, I get an error

Traceback (most recent call last):
  File "parse_get_drivers.py", line 17, in <module>
    data=data.replace(None,"None")
TypeError: replace() argument 1 must be str, not None

Here is my script

import json
import re
from pprint import pprint
import pandas as pd

inHandler = open('get_drivers.txt', 'r')
outHandler = open('drivers.json', 'w')
data = ''


for line in inHandler.readlines():
    print('src:' + line)
    line = line.replace("}]},","}]},\r")
    data += line
    print('replace:' + line)
    data=data.replace("'", '"')
    data=data.replace(None,"None")

outHandler.write(data)

inHandler.close()
outHandler.close()

The required result is to replace None, True and False values with "None", "True" and "False".

Upvotes: 1

Views: 1966

Answers (1)

blhsing
blhsing

Reputation: 106553

You should parse the input as JSON instead of parsing it line by line as separate strings, so that you can recursively traverse the data structure to replace None (or in JSON's terms, null) with "None":

def replace(data, search, replacement, parent=None, index=None):
    if data == search:
        parent[index] = replacement
    elif isinstance(data, (list, dict)):
        for index, item in enumerate(data) if isinstance(data, list) else data.items():
            replace(item, search, replacement, parent=data, index=index)

so that:

import json
d = json.loads('{"a": 1, "b": [1, null], "c": {"d": null}}')
print(d)
replace(d, None, 'None')
print(d)
print(json.dumps(d))

outputs:

{'a': 1, 'b': [1, None], 'c': {'d': None}}
{'a': 1, 'b': [1, 'None'], 'c': {'d': 'None'}}
{"a": 1, "b": [1, "None"], "c": {"d": "None"}}

Upvotes: 1

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