On 11 August 2013 04:43, Chris Angelico <ros...@gmail.com> wrote: > On Sun, Aug 11, 2013 at 4:21 AM, Gary Herron > <gary.her...@islandtraining.com> wrote: >> On 08/10/2013 06:00 PM, Chris Angelico wrote: >>> All it takes is a slightly odd or buggy __eq__ implementation and the >>> == versions will misbehave. To check if an argument is something, you >>> use "is", not ==. >> >> No, sorry, but any use of the word "is" in an English sentence is way too >> ambiguous to specify a correct translation into code. To check "if a >> calculation of some value is a million", you'd write >> value == 1000000 >> not >> value is 1000000 >> even though there are plenty of other examples where "is" would be correct. > > Granted, English is a poor litmus test for code. But in this > particular example, we're talking about immutable types (simple > integers), where value and identity are practically the same. A Python > implementation would be perfectly justified in interning *every* > integer, in which case the 'is' would work perfectly here. The > distinction between the two is important when the objects are mutable > (so they have an identity that's distinct from their current values).
I don't follow this argument. Tuples are immutable yet you're crazy if you check their equality with "is". In Python identity and equality are very distinct. I follow (and agree) with the other arguments: "is" is useful and should be used. It's just this part in particular sounds off. -- http://mail.python.org/mailman/listinfo/python-list
