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pythonjson
Georgi Koemdzhiev
Georgi Koemdzhiev

Reputation: 11931

Iterate through JSON [Python]

I am reading the following JSON file in python:

    {
  "name": "Property",
  "base": "PersistedModel",
  "idInjection": true,
  "options": {
    "validateUpsert": true
  },
  "properties": {
    "uuid": {
      "type": "string"
    },
    "userID": {
      "type": "number"
    },
    "address": {
      "type": "string"
    },
    "price": {
      "type": "number"
    },
    "lastUpdated": {
      "type": "string"
    }
  },
  "validations": [],
  "relations": {
    "rooms": {
      "type": "hasMany",
      "model": "Room",
      "foreignKey": "id"
    },
    "addedByUser": {
      "type": "hasMany",
      "model": "User_ESPC",
      "foreignKey": "id"
    }
  },
  "acls": [],
  "methods": {}
}

I am trying to read the properties and get the name of the property (such as "uuid") and for each name I want to read the type of the object. So far my code lists all of the properties like that:

Property name: price
Property name: userID
Property name: uuid
Property name: lastUpdated
Property name: address

The code that does that is:

import json

#json_file='a.json'
json_file='common/models/property.json'
with open(json_file, 'r') as json_data:
    data = json.load(json_data)


propertyName = data["name"]
properties = data["properties"]

# print (properties)

for property in properties:
    print ('Property name: ' + property)
    # propertyType = property["type"]
    # print (propertyType)

The problem is when I uncomment the bottom 2 lines which should get the type of the property object I get an error:

Property name: price
Traceback (most recent call last):
File "exportPropertyToAndroid.py", line 19, in <module>
propertyType = property["type"]
TypeError: string indices must be integers

Upvotes: 0

Views: 366

Answers (1)

Ilja Everil&#228;
Ilja Everil&#228;

Reputation: 52929

Iterating over a dictionary yields its keys. properties is a dictionary:

properties = data["properties"]

and when you iterate over it in:

for property in properties:
    print ('Property name: ' + property)
    # propertyType = property["type"]
    # print (propertyType)

property references each key in turn. As your dictionary represents JSON data, the keys are strings and the error is quite self explanatory. property["type"] is trying to get a character from the string at the indice "type".

Instead you should either use the key property to fetch additional values from the dictionary:

for property in properties:
    print ('Property name: ' + property)
    propertyType = properties[property]["type"]
    print(propertyType)

or iterate over keys and values:

for property, value in properties.items():
    print ('Property name: ' + property)
    propertyType = value["type"]
    print(propertyType)

Upvotes: 1

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