Blog |

How to Fix TypeError in Python: NoneType Object Is Not Iterable

How to Fix TypeError in Python: NoneType Object Is Not Iterable
Table of Contents

The Python TypeError: NoneType Object Is Not Iterable is an exception that occurs when trying to iterate over a None value. Since in Python, only objects with a value can be iterated over, iterating over a None object raises the TypeError: NoneType Object Is Not Iterable exception.

What Causes TypeError: NoneType Object Is Not Iterable

For an object to be iterable in Python, it must contain a value. Therefore, trying to iterate over a None value raises the Python TypeError: NoneType Object Is Not Iterable exception. Some of the most common sources of None values are:

  • Calling a function that does not return anything.
  • Calling a function that sets the value of the data to None.
  • Setting a variable to None explicitly.

Python TypeError: NoneType Object Is Not Iterable Example

Here’s an example of a Python TypeError: NoneType Object Is Not Iterable thrown when trying iterate over a None value:

mylist = None

for x in mylist:
    print(x)

In the above example, mylist is attempted to be added to be iterated over. Since the value of mylist is None, iterating over it raises a TypeError: NoneType Object Is Not Iterable:

Traceback (most recent call last):
  File "test.py", line 3, in <module>
    for x in mylist:
TypeError: 'NoneType' object is not iterable

How to Fix TypeError in Python: NoneType Object Is Not Iterable

The Python TypeError: NoneType Object Is Not Iterable error can be avoided by checking if a value is None or not before iterating over it. This can help ensure that only objects that have a value are iterated over, which avoids the error.

Using the above approach, a check can be added to the earlier example:

mylist = None

if mylist is not None:
    for x in mylist:
        print(x)

Here, a check is performed to ensure that mylist is not None before it is iterated over, which helps avoid the error.

Track, Analyze and Manage Errors With Rollbar

Managing errors and exceptions in your code is challenging. It can make deploying production code an unnerving experience. Being able to track, analyze, and manage errors in real-time can help you to proceed with more confidence. Rollbar automates error monitoring and triaging, making fixing Python errors easier than ever. Try it today!

Related Posts

See all posts

"Rollbar allows us to go from alerting to impact analysis and resolution in a matter of minutes. Without it we would be flying blind."

Start continuously improving your code today.

Get Started Shape