Robert Kern wrote:
On 2009-03-06 13:46, Gary Herron wrote:
Emanuele D'Arrigo wrote:
Hi everybody,

while testing a module today I stumbled on something that I can work
around but I don't quite understand.

*Do NOT use "is" to compare immutable types.* **Ever! **

Well, "foo is None" is actually recommended practice....


But since newbies are always falling into this trap, it is still a good rule to say:

 Newbies:  Never use "is" to compare immutable types.

and then later point out, for those who have absorbed the first rule:

 Experts: Singleton immutable types *may* be compared with "is",
 although normal equality with == works just as well.

Gary Herron


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