add new value to specific position in JSON using python

Question

I have a JSON file and need to update with new key value pair.

cuurent json:

[{'Name': 'AMAZON',
  'Type': 'Web',
  'eventTimeEpoch': 1611667194}]

I need to add a location parameter and update it as "USA".But when try to update it with below code it append to location parameter with value to end. Like below.

[{'Name': 'AMAZON',
  'Type': 'Web',
  'eventTimeEpoch': 1611667194,
  'location': 'USA'}]

How can I add this location parameter after the Name.

Expected output:

[{'Name': 'AMAZON',
  'location': 'USA',
  'Type': 'Web',
  'eventTimeEpoch': 1611667194
  }]

Current code:

filename='test.json'
jsonFile = open(filename, "r") # Open the JSON file for reading
data = json.load(jsonFile) 
jsonFile.close() 

data[0]["location"] = "USA"
data

In JSON, or Python dictionnary, there is no such concept of "position" for a key. EDIT: wait, I may be wrong here for Python: stackoverflow.com/a/39537308/6213883 — Itération 122442
– Itération 122442, Commented Dec 30, 2022 at 7:43
Does this answer your question? How to keep keys/values in same order as declared? — Cow
– Cow, Commented Dec 30, 2022 at 7:46

S.B · Accepted Answer · 2022-12-30 07:57:23Z

4

First off, your current JSON file is not correctly formatted. JSON needs double quotes not single quotes.

While the order of the inserted key-value pairs is guaranteed to be preserved in Python 3.7 above, you don't have any option to "insert" to specific location inside a dictionary.(like list for example.) And people usually don't count on the order of the keys when working with JSON files. You get your values by "keys" anyway.

With that being said, you can do something like:

import json

with open("test.json") as f:
    data = json.load(f)
    print(data)

new_d = {"Name": data[0].pop("Name"), "location": "USA", **data[0]}
print(new_d)

This way we created a new dictionary with the desired order. Since "location" key is near to the start of the items, we pop first key-value pair, then insert the "location" key, then unpack the rest with ** operator.

edited Dec 30, 2022 at 7:57

answered Dec 30, 2022 at 7:51

S.B

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3 Comments

Adam Over a year ago

Thanks!!!Could you please clarify one thing. You pop the first key value('Name': 'AMAZON') and add the location and then unpack. If so why the location doesnt come as first key value. Since now location is the first key value after the removing "Name"

S.B Over a year ago

@Adam new_d is a separate dictionary from data[0]. Yes after we popped 'name', data[0]'s content is {'Type': 'Web', 'eventTimeEpoch': 1611667194}. Now in new_d, we have the popped item as the first item, "location" as the second item and the rest of the data[0] which is {'Type': 'Web', 'eventTimeEpoch': 1611667194} as the third and forth. Did I able to explain it clearly?

Adam Over a year ago

Perfectly explained!!! Thanks again

Anjana Padmanabhan · Accepted Answer · 2022-12-30 07:57:35Z

2

But you can do a simple hack to keep it in the same order using the dictionary as well, Like this

In [4]: d = [{'Name': 'AMAZON',
   ...:   'Type': 'Web',
   ...:   'eventTimeEpoch': 1611667194}]

In [5]: pos = list(d[0].keys()).index('Name')
   ...: items = list(d[0].items())
   ...: items.insert(pos+1, ('location', 'USA'))
   ...: d[0] = dict(items)

In [6]: print(d)
Out[6]: 
[{'Name': 'AMAZON',
  'location': 'USA',
  'Type': 'Web',
  'eventTimeEpoch': 1611667194}]

edited Dec 30, 2022 at 7:57

answered Dec 30, 2022 at 7:51

Anjana Padmanabhan

212 bronze badges

1 Comment

S.B Over a year ago

Python's builtin dict already preserves the order(3.7+). No need for OrderDict for that.

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