[Python-Dev] Equality testing

Ethan Furman ethan at stoneleaf.us
Wed May 18 20:51:54 CEST 2011


In Python 3 inequality comparisons became forbidden.

--> 123 < [1, 2, 3]
Traceback (most recent call last):
   File "<stdin>", line 1, in <module>
TypeError: unorderable types: int() < list()

However, equality comparisons are still allowed

--> 123 == [1, 2, 3]
False

But you can't mix them (inequality wins)

--> 123 <= [1, 2, 3]
Traceback (most recent call last):
   File "<stdin>", line 1, in <module>
TypeError: unorderable types: int() <= list()

I realize this is probably a Py4000 change if it happens at all, but 
does this make sense?  Shouldn't an attempt to compare to unlike objects 
be a TypeError, just like trying to order them is?

It bit me when I tried to compare a byte string element with a single 
character byte string (of course they should have matched, but since the 
element was an int, the match was not longer True).

~Ethan~


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