Creating a JSON Array in Python using contents from a file

Question

Well, I have a list of numbers inside of a file called "codes.txt", and I'm trying to sort them into an array like this:

{
  codes: [
    "430490",
    "348327",
    "923489"
  ]
}

Or just simply ["430490", "348327", "923489"]. How would I do this? I'm not trying to output this into a file, but create a variable that contains that JSON array. I have this so far:

codefile = open('codes.txt', 'r')
codelist = logfile.readlines()
codefile.close()
for line in codelist:
  # ?

Please tell a bit more about how the codes.txt looks and how the data is present in it — Rishi
– Rishi, Commented Mar 4, 2022 at 16:19
We need to see the input lines. Also, you don’t create a JSON array in Python (or even JavaScript). In Python you create a dict, like you showed, and when you’re ready to save it disk, or share it, you give that dict a JSON serializer which creates the JSON (and can also save it to disk). — Zach Young
– Zach Young, Commented Mar 4, 2022 at 16:25
What you've described isn't valid JSON. Are you sure you're working with JSON? — BrokenBenchmark
– BrokenBenchmark, Commented Mar 4, 2022 at 16:25

jkoestinger · Accepted Answer · 2022-03-04 16:55:01Z

1

I think you pretty much have it correct already:

codefile = open('codes.txt', 'r')
codelist = codefile.readlines()
codefile.close()
data = {
    'codes': [code.strip() for code in codelist]
}

# This is a dict, if you need real json:

import json
data_json = json.dumps(data)

Edit: the code was wrong, it has been corrected and tried with the following content for codes.txt

430490
348327
923489

edited Mar 4, 2022 at 16:55

answered Mar 4, 2022 at 16:20

jkoestinger

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5 Comments

quamrana Over a year ago

You seem to be pretty sure that this code will work. What contents of 'code.txt' did you try this with and what does value does data_json have?

jkoestinger Over a year ago

you're right, it was incorrect, my bad. I fixed it and provided the example used for codes.txt

779804 Over a year ago

I receive this error whenever I try it: 'TypeError: the JSON object must be str, bytes or bytearray, not dict'

jkoestinger Over a year ago

Before my edit the last line was executing json.loads, which is the opposite operation (it loads a json string as a dict). This leads to the error you just reported

779804 Over a year ago

Oh wait, I didn't realise you changed loads to dumps, nevermind. It worked perfectly, thanks!

md2perpe · Accepted Answer · 2022-03-04 16:43:43Z

0

This should be enough:

with open('codes.txt', 'r') as codefile:
    data = {
        'codes': list(codefile)
    }

answered Mar 4, 2022 at 16:43

md2perpe

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