Question

Why does the following piece behave like it behaves?

>>> '10' > 100
True
>>> 100 < '10'
True

Shouldn’t it raise an exception?

Answer 1

From the documentation:

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.

So it’s just something that happens in CPython ('int' < 'str'), but that isn’t guaranteed to happen in other implementations.

In fact, this behaviour has been removed in python3:

>>> '10' > 100
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unorderable types: str() > int()
>>> 100 < '10'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unorderable types: int() < str()