Data Type - NoneType for Nothing

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∟Data Type - NoneType for Nothing

This section describes the NoneType data type, which only has a single object, the null object.

What Is the "NoneType"? "NoneType", also called "None", is the most simplest data type in Python. It has a single object, the null object, representing nothing. And it has with the following features:

1. The null object can be referred by the keyword, None, in Python code.

2. The null object is implicitly casted to True in a Boolean context.

>>> if None:
...     print("Yes")
... else:
...     print("No")
...
No

3. The null object is commonly used as the return value from functions/methods where nothing needs to be returned.

>>> l = ["apple", "banana", "cherry"]
>>> res = l.append("orange")
>>> l
['apple', 'banana', 'cherry', 'orange']

>>> type(res)
<class 'NoneType'>

4. The null object is actually stored in memory, with an identifier and some storage space:

>>> id(None)
4547296864

>>> import sys
>>> sys.getsizeof(None)
16

5. The only operations you can perform in the null object is == and != with any objects of any type. The null object is not equal to any other non-null objects:

>>> None == None
True
>>> None != None
False

>>> None == 0
False
>>> None != 0
True

>>> None == False
False
>>> None != False
True

>>> None == []
False
>>> None == ()
False
>>> None == {}
False