None — Advanced Examples

Represents the absence of a value; Python's null equivalent

EasyIntermediateAdvancedExpert

NoneType singleton behavior

Understanding that None is a singleton.

python
# None is a singleton
a = None
b = None
print(f"a is b: {a is b}")
print(f"id(a) == id(b): {id(a) == id(b)}")

# NoneType can't be instantiated
print(f"type(None): {type(None)}")

# None in containers
values = [1, None, "hello", None, 3]
non_none = [v for v in values if v is not None]
print(f"Filtered: {non_none}")

# None is falsy but not equal to other falsy values
print(f"None == False: {None == False}")
print(f"None == 0: {None == 0}")
print(f"None == '': {None == ''}")

None is a singleton — there is only ever one None object in memory. It is falsy but not equal to other falsy values like 0, False, or ''.

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