'is' vs '==' in Python – What's the Difference? (And When to Use Each)

It's easy to get tripped up by Python's "is" and "==" operators for object comparison. In this video I'll explain the difference with a few easy to understand examples.

There's a difference in meaning between equal and identical. And this difference is important when you want to understand how Python's is and == comparison operators behave.

The == operator compares by checking for equality - the "is" operator, however, compares identities.

The difference between them breaks down to down to two short definitions:

An is expression evaluates to True if two variables point to the same (identical) object.

An == expression evaluates to True if the objects referred to by the variables are equal (have the same contents).

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[TheMultipower]

a = [1, 2, 3]
b = a

c = [1, 2, 3]

print(a==c)
print(a is c)

Output:
True
False

[Creuilcreuil]

"is" statement is a syntactic sugar for "id(a) == id(b)"

[behi]

I think it's easiest to explain is that if "something is something" it just points to the same address in the memory, while "something == something" gives the same result, but both of the "somethings" are occupying a different "memory slot".

[BUDA]

is : equal pointers, == : equal content

[mounirben]

And this "is" very good video, thanks !

[mikeafter]

Thanks! Short examples are very handy.

[finfims]

Thanks, I already new this in my head but couldn't quite explain it but this helped understand exactly how it operates!

[yougugu]

this is so awesome - thank you so much

[kunalsoni]

your video and sound quality is great ❤️

[annazaitseva]

What are the cases when it is needed to identify the same object (by "is")?

[tonyjames]

@Daniel Bader, Good Initiative, this was really helpful.
Hope to see a lot more tips soon

[salmanali]

quality of content!!!
appreciate your work. thanks alot.

[allainegaming]

twin cats that's adorable Dan Bader!

[santoshsingh]

Hey Man, you are doing really awesome job... Thanks for the info man. Cheers!!!(Hoping to get python tricks book)

[AbhishekSingh-witw]

Hi Dan,
Love this series of videos . Thanks a lot!!!
I had a query though regarding is and == Consider the following program:
A = 500
B = 500
Print(a is b)
Result :
Using console mode -> False
Using python script -> True
On further digging found that in console mode u get True for all values till 256 and False otherwise. But in script mode u get True always. could you explain this please ?

[ramstein]

I´m doing python dev for a long time and never user the "as" keywork. Is that a good trick ?
For example in Exception as e, i can then use the details of the exception. Without the "as" i cannot.. learn that yesterday.

[matthewkane]

Great explanation!! Quick question for Dan: I realize you're using the python REPL, but how do you get those autocomplete features when you start typing? Thanks in advance!

[shrav]

hey dan, thanks for the video. What is the editor your using.

[RaabStephan]

"It depends upon what the meaning of the word 'is' is"
- Bill Clinton

[tamiryehuda]

I think the best illustration here is,
b[1] = 7
print(a)
print(b)
print(c)

Great videos, Dan.