Validate dicts in Python

Question

i looking for tool, or examples to/how to validate dictionaries in python.
For example, i have dict:

test = {'foo' : 'bar', 'nested' : {'foo1' : 'bar1', 'foo2' : 'bar2'} }

And now i must validate it. Lets say, value for key foo must be boolean False or non-empty string. Next, if key foo1 have value bar1, that key foo2 must be int in range 1..10. I wrote simple function to do this, but this is not what i exactly want. Yea, sure, i can test every single item in dict with if..else, but if dict have >50 elements, then it is a bit not comfortable.

Is there any good tool/lib to do this in Python? I not looking for parsers, only fast and effective way to do this right.

this is a rare case. I think there are no parsers for this specific task. Maybe you can use `map` function over dict. — ahmet alp balkan, May 15 '11 at 23:18
**See also**: https://stackoverflow.com/questions/45346374/python-schema-to-have-at-least-one-key — dreftymac, Sep 29 '17 at 15:36

score 29 · Accepted Answer · answered May 15 '11 at 23:43

29

Voluptous is a nice tool that does this http://pypi.python.org/pypi/voluptuous

answered May 15 '11 at 23:43

anijhaw

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Exactly what i want. Thank you :) – Galmi May 15 '11 at 23:49

score 4 · Answer 2 · answered Jan 06 '14 at 09:50

4

You can also try the link below:
https://github.com/sunlightlabs/validictory
Its a great package that helps in validation in an easier way

answered Jan 06 '14 at 09:50

Vidz

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Depreciated from 2018, you need to use jsonschema instead. – Izaya Nov 25 '20 at 18:38

Kamil Sindi · Answer 3 · 2016-08-10T19:09:50.053

3

I highly recommend Cerberus for its readability or jsonschema because it uses the JSON Schema standard

edited Aug 10 '16 at 19:09

answered Jul 23 '16 at 18:42

Kamil Sindi

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score 0 · Answer 4 · answered Feb 12 '15 at 20:51

0

Webster is a pypi package that does dictionary validation and value regex validation.. this allows you to insure that the dictionary has all the keys its supposed to and the values are more or less what you would expect.

https://pypi.python.org/pypi/Webster

answered Feb 12 '15 at 20:51

David Lenwell

1

1

since this was a 4 years old question with an already accepted answer it would better if you give more details. Are you proposing a more innovative solution ? If yes please explain it. Have you replicated the example proposed ? – aberna Feb 12 '15 at 20:59

score 0 · Answer 5 · answered Jun 29 '20 at 21:40

This dict-schema-validator package is a very simple way to validate python dictionaries.

Here is a simple schema representing a Customer:

{
  "_id":          "ObjectId",
  "created":      "date",
  "is_active":    "bool",
  "fullname":     "string",
  "age":          ["int", "null"],
  "contact": {
    "phone":      "string",
    "email":      "string"
  },
  "cards": [{
    "type":       "string",
    "expires":    "date"
  }]
}

Validation:

from datetime import datetime
import json
from dict_schema_validator import validator


with open('models/customer.json', 'r') as j:
    schema = json.loads(j.read())

customer = {
    "_id":          123,
    "created":      datetime.now(),
    "is_active":    True,
    "fullname":     "Jorge York",
    "age":          32,
    "contact": {
        "phone":    "559-940-1435",
        "email":    "york@example.com",
        "skype":    "j.york123"
    },
    "cards": [
        {"type": "visa", "expires": "12/2029"},
        {"type": "visa"},
    ]
}

errors = validator.validate(schema, customer)
for err in errors:
    print(err['msg'])

Output:

[*] "_id" has wrong type. Expected: "ObjectId", found: "int"
[+] Extra field: "contact.skype" having type: "str"
[*] "cards[0].expires" has wrong type. Expected: "date", found: "str"
[-] Missing field: "cards[1].expires"

Validate dicts in Python

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