How to Avoid Errors When Accessing JSON Data from Python Dictionaries

JSON Encoding/Decoding with Python

For seamless data exchange and storage, converting Python dictionaries to JSON (JavaScript Object Notation) is a common requirement. However, unexpected errors can arise when attempting to access JSON data from a dictionary.

Error Encountered:

Consider the following code snippet:

<code class="python">r = {'is_claimed': 'True', 'rating': 3.5}
r = json.dumps(r)
file.write(str(r['rating']))</code>

When attempting to access the 'rating' key from the JSON string, a "TypeError: string indices must be integers, not str" error occurs. This error arises because json.dumps() converts the dictionary 'r' into a string, not an actual JSON object or dictionary.

Correct Approach:

To resolve this issue, utilize the json.loads() method to load the JSON string back into a dictionary. This allows you to access the 'rating' key as follows:

<code class="python">import json

r = {'is_claimed': 'True', 'rating': 3.5}
r = json.dumps(r)
loaded_r = json.loads(r)
print(loaded_r['rating'])</code>

Understanding the Distinction:

json.dumps() saves a dictionary as a string, while json.loads() retrieves it as a dictionary. Remember to use json.dumps() when serializing data and json.loads() when deserializing it.

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