json string format done differently

Question

I have 2 lists - dates and weekdays

>>> dates
['2022-02-08', '2022-02-09', '2022-02-10', '2022-02-11', '2022-02-12', '2022-02-13', '2022-02-14', '2022-02-15']
>>> weekdays
['Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday', 'Monday', 'Tuesday']

I want to create a json object that looks like this (for eg) for each element in dates.

myjson = {"label": "Tuesday-2022-02-08", "value": "/inform_date{\"date_list\": \"2022-02-08\"}"}

Basically I want to run a loop where myjson looks like what is given above.

data = []
for i in range(len(dates)):
  myjson = {"label": "{0}-{1}".format(weekdays[i], dates[i]), "value": "/inform_date{\"date_list\": \"{}\"}".format(dates[i])}
  data.append(myjson)

but I get an error when I run the above for loop.

What is the correct way to build myjson so that it looks just like shown in the example above?

inside of format strings, curly braces that you want in the output need to be "escaped" by doubling them up. `f"I want this brace ->{{"` — JonSG, Feb 08 '22 at 14:26

Corralien · Accepted Answer · 2022-02-08T15:31:01.800

1

Use a comprehension and f-strings:

import json

data = [{'label': f"{w}-{d}", 'value': f'/inform_date{{"date_list": "{d}"}}'}
            for d, w in zip(dates, weekdays)]
print(json.dumps(data, indent=4))

[
    {
        "label": "Tuesday-2022-02-08",
        "value": "/inform_date{\"date_list\": \"2022-02-08\"}"
    },
    {
        "label": "Wednesday-2022-02-09",
        "value": "/inform_date{\"date_list\": \"2022-02-09\"}"
    },
    {
        "label": "Thursday-2022-02-10",
        "value": "/inform_date{\"date_list\": \"2022-02-10\"}"
    },
    {
        "label": "Friday-2022-02-11",
        "value": "/inform_date{\"date_list\": \"2022-02-11\"}"
    },
    {
        "label": "Saturday-2022-02-12",
        "value": "/inform_date{\"date_list\": \"2022-02-12\"}"
    },
    {
        "label": "Sunday-2022-02-13",
        "value": "/inform_date{\"date_list\": \"2022-02-13\"}"
    },
    {
        "label": "Monday-2022-02-14",
        "value": "/inform_date{\"date_list\": \"2022-02-14\"}"
    },
    {
        "label": "Tuesday-2022-02-15",
        "value": "/inform_date{\"date_list\": \"2022-02-15\"}"
    }
]

edited Feb 08 '22 at 15:31

answered Feb 08 '22 at 14:23

Corralien

109,409
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52

The dates need to be in quotes too. It should be \"2022-02-08\" instead of 2022-02-08 – user882763 Feb 08 '22 at 14:38
I get 2 slashes insted on single backslash on my windows 10 machine - – user882763 Feb 08 '22 at 15:53
>>> x = json.dumps(data) >>> x '[{"label": "Tuesday-2022-02-08", "value": "/inform_date{\\"date_list\\": \\"2022-02-08\\"}"}, {"label": "Wednesday-2022-02-09", "value": "/inform_date{\\"date_list\\": \\"2022-02-09\\"}"}, {"label": "Thursday-2022-02-10", "value": "/inform_date{\\"date_list\\": \\"2022-02-10\\"}"}, {"label": "Friday-2022-02-11", "value": "/inform_date{\\"date_list\\": \\"2022-02-11\\"}"}, {"label": "Saturday-2022-02-12", "value": "/inform_date{\\"date_list\\": \\"2022-02-12\\"}"}, ]' – user882763 Feb 08 '22 at 15:54
Use print(x). It's just the escape mecanisem of python to display the representation of a string. – Corralien Feb 08 '22 at 16:00

score 0 · Answer 2 · answered Feb 08 '22 at 14:21

0

Your second format string has 'spare' braces which need to be escaped:

myjson = {"label": "{0}-{1}".format(weekdays[i], dates[i]), "value": "/inform_date{{\"date_list\": \"{}\"}}".format(dates[i])}

answered Feb 08 '22 at 14:21

quamrana

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json string format done differently

2 Answers2