None

In addition to the standard types such as Strings and Numbers, Python has a special data type that defines a single special data object called None. As the name suggests, None is used to represent an empty value. It appears in various forms in Python.

None is often useful in everyday Python programming as a placeholder to indicate a data structure where meaningful data can eventually be found, even if that data has not yet been calculated.

The presence of None is easy to check, as there is only one instance of None in Python (all references to None point to the same object), and None is only identical to itself:

>>> MyType = type(None)
>>> MyType() is None
True

None is falsy

In Python, we often rely on the fact that None is falsy:

>>> bool(None)
False

For example, we can check whether Strings are empty in an if statement:

>>> myval = ""
>>> if not myval:
...     print("No value was specified.")
...
No value was specified.

None stands for emptiness

>>> titles = {7.0: "Data Types", 7.1: "Lists", 7.2: "Tuples"}
>>> third_title = titles.get("7.3")
>>> print(third_title)
None

The default return value of a function is None

For example, a procedure in Python is just a function that does not explicitly return a value, which means that it returns None by default:

>>> def myfunc():
...     pass
...
>>> print(myfunc())
None