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In Python, None evaluates to less than zero?
ActivePython 2.7.2.5 (ActiveState Software Inc.) based on Python 2.7.2 (default, Jun 24 2011, 12:21:10) [MSC v.1500 32 bit (Intel)] on win 32 Type "help", "copyright", "credits" or "license" for more information. >>> None < 0 True >>> None == 0 False >>> None > 0 False >>> Is this expected?
I would have guessed that None would either be equal to zero (through type coercion), or that all of these statements would return False.
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As the null in Python, None is not defined to be 0 or any other value. In Python, None is an object and a first-class citizen!
In Python, None represents an absence of a value in a variable. In Python, None is what would be a null in other commonly used programming languages. Unlike the null in the other languages, Python's None has nothing to do with values 0 or False for example.
However, None evaluates to False, so the or operator returns the first "True" value, which is the second value. We have to modify the code so that both the or arguments are True.
Introduction to the Python None value It means that Python creates one and only one None object at runtime. It's a good practice to use the is or is not operator to compare a value with None . Note that you cannot override the is operator behavior like you do with the equality operator ( == ).
See the manual:
Objects of different types, except different numeric types and different string types, never compare equal; such objects are ordered consistently but arbitrarily (so that sorting a heterogeneous array yields a consistent result).
and
CPython implementation detail: Objects of different types except numbers are ordered by their type names; objects of the same types that don’t support proper comparison are ordered by their address.
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From the docs:
CPython implementation detail: Objects of different types except numbers are ordered by their type names; objects of the same types that don’t support proper comparison are ordered by their address.
NoneType compares as smaller than int since the comparison appears to be case-sensitive.
>>> type(0) <type 'int'> >>> type(None) <type 'NoneType'> >>> 'NoneType' < 'int' True If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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