convert list of objects to Json array

Question

I'm new to python and i have a list of objects like this.

Sample code

>>> for val in las.version:
...     print(val.mnemonic)
...     print(val.unit)
...     print(val.value)
...     print(val.descr)
...
VERS

1.2
some description
WRAP

NO
another description
>>>

I wanted to convert this as JSON array.

{  
   "versionInformation":[  
      {  
         "mnemonic":"VERS",
         "unit":"",
         "value":"2.0",
         "description":"some description"
      },
      {  
         "mnemonic":"WRAP",
         "unit":"",
         "value":"NO",
         "description":"another description"
      }
   ]
}

your input is a string ?

toheedNiaz
– toheedNiaz

2018-04-24 11:28:51 +00:00
Commented Apr 24, 2018 at 11:28 — toheedNiaz
– toheedNiaz, Commented Apr 24, 2018 at 11:28
@toheedNiaz: its a list of objects called HeaderItem

Shankar
– Shankar

2018-04-24 11:30:23 +00:00
Commented Apr 24, 2018 at 11:30 — Shankar
– Shankar, Commented Apr 24, 2018 at 11:30
What are HeaderItem objects? Where are they coming from?

zwer
– zwer

2018-04-24 11:30:43 +00:00
Commented Apr 24, 2018 at 11:30 — zwer
– zwer, Commented Apr 24, 2018 at 11:30
Input is a ASCII file and everything is text.

Shankar
– Shankar

2018-04-24 11:33:53 +00:00
Commented Apr 24, 2018 at 11:33 — Shankar
– Shankar, Commented Apr 24, 2018 at 11:33
@zwer: I have updated my question.

Shankar
– Shankar

2018-04-24 11:35:20 +00:00
Commented Apr 24, 2018 at 11:35 — Shankar
– Shankar, Commented Apr 24, 2018 at 11:35

zwer · Accepted Answer · 2018-04-24 11:40:36Z

6

Without the HeaderItem description this cannot account for possible errors, but you can easily recreate the JSON structure using dict/list combos and then use the built-in json module to get your desired JSON, i.e.:

import json

version_info = [{"mnemonic": v.mnemonic, "unit": v.unit,
                 "value": v.value, "description": v.descr}
                for v in las.version]
print(json.dumps({"versionInformation": version_info}, indent=3))

Keep in mind that prior to CPython 3.6 and Python 3.7 in general, the order of the items in the JSON of individual version info cannot be guaranteed. You can use collections.OrderedDict instead if that's important - it shouldn't be, tho, given that JSON by specification uses unordered mappings.

answered Apr 24, 2018 at 11:40

zwer

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3 Comments

Shankar Over a year ago

Excellent, exactly what i want.. thanks for the help.

Shankar Over a year ago

I wanted to create single JSON file with different informations, like Version Information, how to add all the informations and write to file?

zwer Over a year ago

@Shankar - Instead of printing the data to STDOUT with json.dumps() use json.dump() to write it to a file. Check this answer as an example.

Yassine Faris · Accepted Answer · 2018-04-24 11:49:14Z

3

from pprint import pprint


result = {}
result['versionInformation'] = []

for val in las.version:
    version_info = {}
    version_info['mnemonic'] = val.mnemonic
    version_info['unit'] = val.unit
    version_info['value'] = val.value
    version_info['description'] = val.descr

    result['versionInformation'].append(version_info)


pprint(result)

edited Apr 24, 2018 at 11:49

answered Apr 24, 2018 at 11:38

Yassine Faris

1,0118 silver badges28 bronze badges

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