Avetis KAZARIAN wrote:
Gary Herron wrote:The question now is: Why do you care? The properties of strings do not depend on the implementation's choice, so you shouldn't care because of programming considerations. Perhaps it's just a matter of curiosity on your part.Gary HerronWell, it's not about curiosity, it's more about performance. I will make a PHP example (a really quite simple ) PHP : Stat 1 : $aVeryLongString == $anOtherVeryLongString Stat 2 : $aVeryLongString === $anOtherVeryLongString Stat 2 is really faster than Stat 1 (due to the binary comparison) As I said, I'm coming from PHP, so I was wondering if there was such a difference in Python.
Please keep in mind in both cases there is nothing "for free". To have identity, you would need to have the same object - which in case of a string means the interpreter has to find out about existing string with exactly the same contents and reference it instead of creating a new object in memory. This takes about at least the same time (if not more) then just run the compare with both strings when you need (aka == ). If you only have a few strings but compare them often, you could profit from identity and the overhead of installing it would be neglectable (and you can force this in python with "internal") but in this case I'd think calculating and working with a hash instead should be preferred. Regards Tino Wildenhain
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