Why does the "is" keyword have a different behavior when there is a dot in the string? Question: Consider this code: >>> x = “google” >>> x is “google” True >>> x = “google.com” >>> x is “google.com” False >>> Why is it like that? To make sure the above is correct, I have just …
Is False == 0 and True == 1 an implementation detail or is it guaranteed by the language? Question: Is it guaranteed that False == 0 and True == 1, in Python (assuming that they are not reassigned by the user)? For instance, is it in any way guaranteed that the following code will always …
Why does comparing strings using either '==' or 'is' sometimes produce a different result? Question: Two string variables are set to the same value. s1 == s2 always returns True, but s1 is s2 sometimes returns False. If I open my Python interpreter and do the same is comparison, it succeeds: >>> s1 = ‘text’ …
Compare object instances for equality by their attributes Question: I have a class MyClass, which contains two member variables foo and bar: class MyClass: def __init__(self, foo, bar): self.foo = foo self.bar = bar I have two instances of this class, each of which has identical values for foo and bar: x = MyClass(‘foo’, ‘bar’) …
Elegant ways to support equivalence ("equality") in Python classes Question: When writing custom classes it is often important to allow equivalence by means of the == and != operators. In Python, this is made possible by implementing the __eq__ and __ne__ special methods, respectively. The easiest way I’ve found to do this is the following …
Is there a difference between "==" and "is"? Question: My Google-fu has failed me. In Python, are the following two tests for equality equivalent? n = 5 # Test one. if n == 5: print ‘Yay!’ # Test two. if n is 5: print ‘Yay!’ Does this hold true for objects where you would be …
