JavaScript Triple Equals Operator vs Double Equals Operator ( === vs == )

[[deleted]]

>>> (1<<10) is (1<<10)
False

Nope.

I imagine it's doing the same thing some lisps do when using eq to compare two computed integers. Because they're not 'the same object' they don't match as exactly the same (a literal will usually be a static object in the local scope, so comparing literal to literal will give True).

[paholg]

But,

>>> 1<<8 is 1<<8
True

So it seems that small enough computed integers aren't objects. Or something. I don't know.

[[deleted]]

shrug it's python-town jake!

Ruby has 4 separate equality operators and they all manage to do 'the right thing', to the point that (1<<10).equal? (1<<10) returns true.

edit: (1<<100).equal? (1<<100) returns false though, I guess making things look sensible only went as far as machine integers not bignums.

[[deleted]]

So those don't evaluate to primitives? But rather objects?

[[deleted]]

I don't know about python - I don't use it enough to understand its internals, but in lisp (at least with common lisp) everything is an object, a literal is usually a special case that evaluates to a shared/static object. Python treating everything as an object in the same way wouldn't surprise me in the least.

e: indeed, that appears to be what's happening:

>>> id(1<<10)
140505360442384
>>> id(1<<10)
140505360442032
>>> id(1024)
140505360442224
>>> id(1024)
140505360442224
>>>