`==` checks for value equality, while `is` checks for object identity. Use `==` for comparing values and `is` for checking if two references point to the same object.

In Python, understanding the difference between == and is is essential for effective comparison of objects. The == operator checks for value equality, meaning it evaluates whether the values of two objects are the same. For example:

x = [1, 2, 3]
y = [1, 2, 3]
print(x == y)  # Output: True

Here, x and y have the same contents, so x == y evaluates to True. In contrast, the is operator checks for object identity, meaning it evaluates whether two references point to the same object in memory:

print(x is y)  # Output: False

Even though x and y have the same contents, they are different objects in memory. To illustrate further:

z = x
print(x is z)  # Output: True

In this case, z is a reference to x, so x is z evaluates to True. Use == when you want to compare the values of objects and is when you need to check if two references point to the same object.