Check for None (Null) in Python
If you’ve used other programming languages, you may have learned that an empty object is not the same as an object that does not exist. In this lesson, you’ll learn how to check for None (or Null objects) in Python.
In Python, null variables are known as none. Let's create a variable and set it to none. The correct way to check for this is with the is operator. There's another way you could do it. You could do if fu=none and that works, but it's not the preferred way in Python.
Let me show you why. If I do id(fu), it gives me the ID of the variable fu, and in Python everything has an ID and a value. Whenever we use the is operator, it does an ID comparison, whereas if we use the equals, then it requires a [inaudible 0:45] to look up and has to iterate through it to do the comparison. The end result is the is, is much faster than using equals when checking for none.