Json load python extra data

Last updated: Feb 17, 2023
Reading time · 4 min

banner

# json.decoder.JSONDecodeError: Extra data in Python

The Python «json.decoder.JSONDecodeError: Extra data» occurs when we try to parse multiple objects without wrapping them in an array.

To solve the error, wrap the JSON objects in an array or declare a new property that points to an array value that contains the objects.

Here is a very simple example of how the error occurs.

Copied!
import json # ⛔️ json.decoder.JSONDecodeError: Extra data: line 1 column 10 (char 9) result = json.loads(r'')

We are trying to parse 2 objects next to one another without the objects being elements in an array.

There are 3 main ways to solve the error:

Wrap the objects in an array.
Set an array property on the object that contains the multiple objects.
Iterate over the objects and parse each object.

# Wrap the JSON objects in a List to solve the error

One way to solve the error is to wrap the objects in an array and separate them by a comma.

Copied!
# ✅ an array of objects import json result = json.loads(r'[, ]')

Notice that we wrapped the objects in square brackets to create a JSON array.

Make sure to separate the objects in the array by a comma.

However, they shouldn’t be a comma after the last object.

Copied!
import json # ✅ correct (no trailing comma) a_list = json.loads(r'[, ]') # ⛔️ incorrect (has trailing comma) a_list = json.loads(r'[, ,]')

If you add a comma after the last object, a parsing error is raised.

# Solve the error when reading from a JSON file

Here is an example of how the error occurs while reading a file.

Copied!
import json file_name = 'example.json' with open(file_name, 'r', encoding='utf-8') as f: # ⛔️ json.decoder.JSONDecodeError: Extra data: line 2 column 3 (char 42) my_data = json.load(f) print(my_data)

Here is the content of the example.json file.

Copied!
"id": 1, "name": "Alice", "age": 30> "id": 2, "name": "Bob", "age": 35> "id": 3, "name": "Carl", "age": 40>

Having multiple objects that are not wrapped in an array is not valid JSON.

One way to solve the issue is to wrap the JSON objects in an array and use commas to separate the elements.

Copied!
[ "id": 1, "name": "Alice", "age": 30>, "id": 2, "name": "Bob", "age": 35>, "id": 3, "name": "Carl", "age": 40> ]

We create a list by wrapping the objects in square brackets.

Notice that there isn’t a comma after the last element in the array.

Now we can read the file without getting an error.

Copied!
import json file_name = 'example.json' with open(file_name, 'r', encoding='utf-8') as f: my_data = json.load(f) # 👇️ [, , ] print(my_data) print(my_data[0]['id']) # 👉️ 1 print(my_data[0]['name']) # 👉️ Alice

Having an array of comma-separated objects is perfectly valid JSON, so everything works as expected.

# Add an array property to the JSON object

Alternatively, you can add a new property to the JSON object.

Copied!
 "employees": [ "id": 1, "name": "Alice", "age": 30>, "id": 2, "name": "Bob", "age": 35>, "id": 3, "name": "Carl", "age": 40> ] >

Now parsing the JSON file would get us a Python dictionary.

Copied!
import json file_name = 'example.json' with open(file_name, 'r', encoding='utf-8') as f: my_data = json.load(f) # 👇️ , , ]> print(my_data)

The dictionary has an employees key that is an array of objects.

# Parsing each individual line in a list comprehension

If you have no control over the JSON data, try using a list comprehension and parse each individual line.

Imagine that we have the following JSON.

Copied!
"id": 1, "name": "Alice", "age": 30> "id": 2, "name": "Bob", "age": 35> "id": 3, "name": "Carl", "age": 40>

Here is a list comprehension that parses each individual line.

Copied!
import json data = [json.loads(line) for line in open('example.json', 'r', encoding='utf-8')] # 👇️ [, , ] print(data)

We use the json.loads method to parse each line into a native Python object and add the lines to a list.

However, this would only work if each line contains valid JSON.

The fastest way to validate and correct your JSON is to use a JSON validator.

Paste your payload into the form as the validator checks for errors and sometimes directly fixes them.

If you are fetching data from a remote API, then you have to look into the data the API returns and correct the issue on the backend.

# Having multiple arrays next to one another

The error is also raised if you have multiple arrays next to one another without them being wrapped in another array.

Copied!
import json # ⛔️ json.decoder.JSONDecodeError: Extra data: line 1 column 11 (char 10) result = json.loads(r'["a", "b"]["c", "d"]')

One way to solve the error is to add the elements to a single array.

Copied!
import json result = json.loads(r'["a", "b", "c", "d"]') print(result) # 👉️ ['a', 'b', 'c', 'd'] print(result[0]) # 👉️ a print(result[1]) # 👉️ b

Notice that we used only one set of square brackets.

Another way to solve the error is to use a two-dimensional array.

Copied!
import json result = json.loads(r'[["a", "b"], ["c", "d"]]') print(result) # 👉️ [['a', 'b'], ['c', 'd']] print(result[0]) # 👉️ ['a', 'b'] print(result[1]) # 👉️ ['c', 'd'] print(result[0][0]) # 👉️ a print(result[1][0]) # 👉️ c

Python indexes are zero-based, so the first item in a list has an index of 0 , and the last item has an index of -1 or len(a_list) — 1 .

A third way to solve the error is to add the arrays as properties on an object.

Copied!
import json result = json.loads(r'') # 👇️ print(result) print(result['first']) # 👉️ ['a', 'b'] print(result['second']) # 👉️ ['c', 'd'] print(result['first'][0]) # 👉️ a print(result['second'][0]) # 👉️ c

The arrays are now values of the first and second properties, so the string is valid JSON.

# Additional Resources

You can learn more about the related topics by checking out the following tutorials:

I wrote a book in which I share everything I know about how to become a better, more efficient programmer.

Источник

Python json.decoder.JSONDecodeError: Extra data

When working with JSON strings with Python, you might encounter the json.decoder.JSONDecodeError: Extra data error message.

What JSONDecodeError: extra data mean?

A Python JSONDecodeError means that there’s something wrong with the way your JSON data is formatted.

If the error complains about extra data , it means that you are trying to load multiple JSON objects that are formatted incorrectly.

For example, suppose you try to load two JSON objects like this:

, ' The call to json.loads(data) in the example above will cause the following error:

This error happens because the json.load() method doesn’t decode multiple objects.

The JSON format in the example is also wrong because JSON can’t contain multiple objects as root elements.

You can validate your JSON strings using JSONLint.

How to resolve JSONDecodeError: extra data

To resolve this error, you need to wrap multiple JSON objects in a single list.

A Python list is defined using the square brackets notation ( [] ) as follows. Notice how square brackets are added before and after the curly brackets:

How to read multiple JSON objects in Python?

If you get the JSON data from a .json file, then you need to wrap the JSON objects written in that file in a list:

    But keep in mind that you need to have exactly one list in a single .json file.

If you have multiple lists like this:

Then it will also trigger the JSONDecodeError: Extra data error.

If you have exactly one JSON object per line, you can also load them using a list comprehension syntax.

Suppose your .json file looks like this:

Then you can use the list comprehension syntax to read each line and parse it as a list.

Once you have the list, you can access the JSON data as shown below:

Now you’ve learned how to read JSON objects in Python.

Conclusion

Python shows json.decoder.JSONDecodeError: Extra data error message when you try to load JSON data with an invalid format.

To resolve this error, you need to check your JSON data format. If you have multiple objects, wrap them in a list or read them line by line using a list comprehension syntax.

By following the steps in this tutorial, you can easily fix the JSON extra data error.

I hope this tutorial helps. See you again in other articles!

Take your skills to the next level ⚡️

I’m sending out an occasional email with the latest tutorials on programming, web development, and statistics. Drop your email in the box below and I’ll send new stuff straight into your inbox!

About

Hello! This website is dedicated to help you learn tech and data science skills with its step-by-step, beginner-friendly tutorials.
Learn statistics, JavaScript and other programming languages using clear examples written for people.

Search

Type the keyword below and hit enter

Json load python extra data

JSONDecodeError Extra data