BlueJ774 wrote:
> Can someone please explain to me the difference between the "is"
> keyword and the == boolean operator. I can't figure it out on my own
> and I can't find any documentation on it.
>
> I can't understand why this works:
>
> if text is None:
>
> and why this always returns false:
>
> if message is 'PING':
>
> even when message = 'PING'.
>
> What's the deal with that?
`x is y` means the same thing as:
id(x) == id(y)
You use the `is` operator for when you're testing for _object identity_,
not value. `None` is a special object sentinel that is not only a value
but a special _object_, and so if you're testing whether or not an
object is `None`, you do so with the `is` operator.
If you're testing whether an object is equal to the string "PING" then
you do not want to do so by identity, but rather value, so you use the
`==` operator, not `is`.
--
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