Python Operators

Q: What is the difference between is and == in Python?

== compares values, while is checks whether both sides are the exact same object in memory. Use is mainly for comparing with None, True or False.

Q: Does Python have ++ and -- operators?

No. Use x += 1 and x -= 1 instead. Writing ++x is valid but does nothing, because it is just two unary plus signs.

Q: What does % do in Python?

With numbers, % returns the remainder of a division, so 10 % 3 is 1. It is often used to check whether a number is even with n % 2 == 0.

Q: What is the walrus operator in Python?

The := operator, added in Python 3.8, assigns a value to a variable as part of a larger expression, such as inside an if or while condition.

Python operators are symbols and keywords that perform operations on values, such as adding numbers, comparing values or combining conditions. Python groups its operators into a few families, and this chapter walks through each one.

Arithmetic Operators

Use + - * / for the basic operations, // for floor division, % for the remainder (modulus) and ** for powers.

a, b = 17, 5

print(a + b, a - b, a * b)
print(a / b)
print(a // b, a % b)
print(2 ** 10)

Assignment Operators

Besides =, Python has shortcut operators that update a variable in place: x += 3 means x = x + 3. The same pattern works with -=, *=, /=, //=, %= and **=.

balance = 100
balance += 50
balance -= 30
balance *= 2
print(balance)

# The walrus operator assigns inside an expression
if (n := len("python")) > 5:
    print("Long word with", n, "letters")

240
Long word with 6 letters

Comparison Operators

Comparison operators return True or False: == equal, != not equal, > greater than, < less than, >= and <=. Python also lets you chain comparisons the way you would in maths.

age = 25

print(age == 25, age != 30)
print(18 <= age < 65)

True True
True

Python Logical Operators

and is True only when both sides are True. or is True when at least one side is True. not flips a boolean. Python stops evaluating as soon as the answer is known (short-circuiting).

has_ticket = True
is_vip = False

print(has_ticket and is_vip)
print(has_ticket or is_vip)
print(not is_vip)

name = ""
print(name or "Guest")

False
True
True
Guest

The last line shows a common trick: or returns the first truthy value, so name or "Guest" gives a default when name is empty.

Identity and Membership Operators

is checks whether two names point to the very same object, while == checks whether the values are equal. in and not in check whether a value is inside a sequence or collection.

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

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

print(2 in a)
print("z" not in "python")

True
False
True
True
True

Operator Precedence

When an expression has several operators, Python follows a fixed order. From highest to lowest, the main levels are:

() parentheses
** exponent
unary + and - (for example -x)
* / // %
+ -
comparisons, is, in
not, then and, then or

For example 2 + 3 * 4 is 14, not 20, because multiplication happens first. When in doubt, add parentheses; they make the intent obvious to readers too.

Frequently asked questions

What is the difference between is and == in Python?

== compares values, while is checks whether both sides are the exact same object in memory. Use is mainly for comparing with None, True or False.

Does Python have ++ and -- operators?

No. Use x += 1 and x -= 1 instead. Writing ++x is valid but does nothing, because it is just two unary plus signs.

What does % do in Python?

With numbers, % returns the remainder of a division, so 10 % 3 is 1. It is often used to check whether a number is even with n % 2 == 0.

What is the walrus operator in Python?

The := operator, added in Python 3.8, assigns a value to a variable as part of a larger expression, such as inside an if or while condition.