difference between 'is' and '=='
python
Solution
The first checks for identity the second for equality.
Examples:
The first operation using `is` may or may not result in `True` based on where these items, i.e., strings, are stored in memory.
a='this is a very long string'
b='this is a very long string'
a is b
False
Checking, id() shows them stored at different locations.
id(a)
62751232
id(b)
62664432
The second operation (`==`) will give `True` since the strings are equal.
a == b
True
Another example showing that `is` can be `True` or `False` (compare with the first example), but `==` works the way we'd expect:
'3' is '3'
True
this implies that both of these short literals were stored in the same memory location unlike the two longer strings in the example above.
'3' == '3'
True
No surprise here, what we would have expected.
I believe `is` uses id() to determine if the same objects in memory are referred to (see @SvenMarnach comment below for more details)
Problem
Possible Duplicate: Is there any difference between “foo is None” and “foo == None”? Quite a simple question really. Whats the difference between: ``` if a.b is 'something': ``` and ``` if a.b == 'something': ``` excuse my ignorance