"Good Z" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
| Hello,
| I am having problem in using is. Here is what i am doing.
|
| x=''
| if x is None or x is '':
|return 1
x is not the singleton value None, nor is it the newly created null string
object. It is up to the imp
'is' tests for identity (variable references the same memory location) while
'==' tests for equality. Though it's probably best to use 'is' with more
complex classes and not the simpler built-in types like integers.
See how 'is' works for lists below:
>>> l1 = [1,2,3,4]
>>> l3 = [1,2,3,4]
>>> l1
Good Z schrieb:
> Hello,
> I am having problem in using is. Here is what i am doing.
>
> x=''
> if x is None or x is '':
> return 1
>
> The above statement does not return value 1.
>
> If i changed the above check to
> if x == None or x == '':
> return 1
> Now it works fine.
>
Good Z wrote:
Hello,
I am having problem in using is. Here is what i am doing.
Short answer: Use == for equality.Don't use "is". Ever!
(Especially if you are a newbie.)
Longer answer: In a dozen years of programming Python, the only time I
use "is" is when testing for something like
Hello,
I am having problem in using is. Here is what i am doing.
x=''
if x is None or x is '':
return 1
The above statement does not return value 1.
If i changed the above check to
if x == None or x == '':
return 1
Now it works fine.
Any idea. What is happening here. I am usin
