Is there a difference between “==” and “is”?

Question

In Python, are the following two tests for equality equivalent?

# Test one.

n = 5 

if n == 5:

  print 'Yay!'

# Test two. 

if n is 5: 

  print 'Yay!'

Does this hold true for objects where you would be comparing instances (a list say)?

Okay, so this kind of answers my question:

L = []

L.append(1)

if L == [1]: 

print 'Yay!' 

# Holds true, but... 

if L is [1]: 

print 'Yay!' 

# Doesn't.

So == test value where are tests to see if they are the same object?

Answer 1

• There is a simple rule that will tell you when to use == or is the keyword.

• The ‘==’ keyword is used for checking the value equality. You can use it when you would like to know if two objects have the same value.

• The ‘is’ keyword is used for reference equality. You can use it when you would like to know if two references refer to the same object. In other words ‘is’ keyword determines whether the two values are an exact same object and equal.

• Here’s an example that validates the above definition:-

a = 500 

b = 500

a == b 

output:-True 

a is b

Output:-False