Python - Operators

In Python, operators have different levels of precedence, which determine the order in which they are evaluated. When multiple operators are present in an expression, the ones with higher precedence are evaluated first. In the case of operators with the same precedence, their associativity comes into play, determining the order of evaluation.

Operator Precedence and Associativity in Python

Please see the following precedence and associativity table for reference. This table lists all operators from the highest precedence to the lowest precedence.

Precedence	Operators	Description	Associativity
1	()	Parentheses	Left to right
2	x[index], x[index:index]	Subscription, slicing	Left to right
3	await x	Await expression	N/A
4	**	Exponentiation	Right to left
5	+x, -x, ~x	Positive, negative, bitwise NOT	Right to left
6	*, @, /, //, %	Multiplication, matrix, division, floor division, remainder	Left to right
7	+, –	Addition and subtraction	Left to right
8	<<, >>	Shifts	Left to right
9	&	Bitwise AND	Left to right
10	^	Bitwise XOR	Left to right
11	\|	Bitwise OR	Left to right
12	in, not in, is, is not, <, <=, >, >=, !=, ==	Comparisons, membership tests, identity tests	Left to Right
13	not x	Boolean NOT	Right to left
14	and	Boolean AND	Left to right
15	or	Boolean OR	Left to right
16	if-else	Conditional expression	Right to left
17	lambda	Lambda expression	N/A
18	:=	Assignment expression (walrus operator)	Right to left

Precedence of Python Operators

This is used in an expression with more than one operator with different precedence to determine which operation to perform first.

Example

10 + 20 * 30

Precedence Python

10 + 20 * 30 is calculated as 10 + (20 * 30)
and not as (10 + 20) * 30

Python Code of the above Example

Python3

# Precedence of '+' & '*'
expr = 10 + 20 * 30
 
print(expr)

Output

Precedence of Logical Operators in Python

In the given code, the ‘if‘ block is executed even if the age is 0. Because the precedence of logical ‘and‘ is greater than the logical ‘or‘.

Python3

# Precedence of 'or' & 'and'
name = "Alex"
age = 0
 
if name == "Alex" or name == "John" and age >= 2:
    print("Hello! Welcome.")
else:
    print("Good Bye!!")

Output

Hello! Welcome.

Hence, To run the ‘else‘ block we can use parenthesis( ) as their precedence is highest among all the operators.

Python3

# Precedence of 'or' & 'and'
name = "Alex"
age = 0
 
if (name == "Alex" or name == "John") and age >= 2:
    print("Hello! Welcome.")
else:
    print("Good Bye!!")