When you deal with operators in Python, it is essential to understand the concept of Python operator precedence and associativity. It is because they determine the priorities of the operator otherwise we will have unexpected outputs.

**Operator Precedence**

We use this in an expression that has more than one operator with difference precedence to determine which operation must be performed first.

**Example**

Solve25 + 10 * 20

**25 + 10 * 20** is calculated as **25 + (10 * 20)**

and not as **(25 + 10) * 20**

**Code:**

**Python3**

` `filter_noneeditplay_arrowbrightness_4# Precedence of '+' & '*'expr = 25 + 10 * 20print(expr)

**Output:**

` `225

**Browse more Topics UnderVariables, Expressions and Statements**

- Values, Variables and Keywords
- Operators and Operands in Python
- Expressions and Statement
- Taking Input and Displaying Output
- Putting Comments

**Precedence of Python Operators**

We term the combination of values, variables, operators, and function calls as an expression. The Python interpreter can evaluate a valid expression. For instance:

>>> 3 – 8

-5

Over here,3 – 8is an expression. Thus, there can be more than one operator in an expression. Moreover, in order to evaluate these kinds of expressions, there is a rule of precedence in Python. In other words, it guides the order in which these operations carry out.

Operators | Meaning |

() | Parentheses |

** | Exponent |

+x, -x, ~x | Unary plus, Unary minus, Bitwise NOT |

*, /, //, % | Multiplication, Division, Floor division, Modulus |

+, – | Addition, Subtraction |

<<, >> | Bitwise shift operators |

& | Bitwise AND |

^ | Bitwise XOR |

| | Bitwise OR |

==, !=, >, >=, <, <=, is, is not, in, not in | Comparisons, Identity, Membership operators |

not | Logical NOT |

and | Logical AND |

or | Logical OR |

For instance, multiplication has higher precedence than subtraction.

` `# Multiplication has higher precedence# than subtraction>>> 10 - 4 * 22

However, we can change this order by making use of parentheses()as it has higher precedence than multiplication.

` `# Parentheses () has higher precedence>>> (10 - 4) * 212

If you look at the operator precedence in Python in the table mentioned above, you will see it is in descending order. In other words, the upper group has higher precedence than the lower ones.

**Example**

To understand this better, we will take a look at some examples:

Suppose that you are constructing an if…elseblock which runsifwhenbreakfastis eithercerealortoastand only ifmoneyis more than or equal to2.

` `# Precedence of or & andmeal = " cereal"money = 0if meal == " cereal" or meal == " toast" and money >= 2:print("Breakfast being delivered")else:print("Can't deliver breakfast")

**Output**

` `Breakfast being delivered

**Associativity of Python Operators**

The table makes it clear that more than one operator is present in the same group. In other words, these operators have the same precedence. Thus, when two operators have the same precedence, associativity assists in determining the order of operations.

Further, we see that associativity refers to the order in which an expression is assessed that has multiple operators of the same precedence. Similarly, almost all the operators have left-to-right associativity.

For instance, multiplication and floor division have the same precedence. Therefore, if both of them exist in an expression, the left one will be evaluated first.

` `# Left-right associativity# Output: 3print(5 * 2 // 3)# Shows left-right associativity# Output: 0print(5 * (2 // 3))

**Output**

` `30

**Note**: Exponent operator**has right-to-left associativity in Python.

` `# Shows the right-left associativity of **# Output: 512, Since 2**(3**2) = 2**9print(2 ** 3 ** 2)# If 2 needs to be exponated first, need to use ()# Output: 64print((2 ** 3) ** 2)We can see that2 ** 3 ** 2is equivalent to2 ** (3 ** 2).

**Non Associative Operators**

Some operators like assignment operators and comparison operators do not have associativity in Python. Thus, we have separate rules for sequences of this kind of operator and we cannot express them as associativity.

For instance,x < y < zneither means(x < y) < znorx < (y < z).x < y < zis equivalent tox < y and y < z, and is evaluated from left-to-right.

In addition, while chaining of assignments likex = y = z = 1is perfectly valid,x = y = z+= 2will result in error.

` `# Initialize x, y, zx = y = z = 1# Expression is invalid# (Non-associative operators)# SyntaxError: invalid syntaxx = y = z+= 2

**Output**

` `File "", line 8x = y = z+= 2^SyntaxError: invalid syntax

**FAQ on Operator Precedence**

**Question 1: Which is the order of precedence in Python?**

**Answer 1:** Python follows the same precedence rules for its mathematical operators just like mathematics.Further, parentheseshave the highest precedence we can use them to force an expression to evaluate in the order one wants. Moreover, as we evaluate expressions first inparentheses, 3 * (2-1) is 3, and (1+1)**(5-2) is 8.

**Question 2: What is the precedence of logical operators?**

**Answer 2:** The order ofprecedenceislogicalcomplements ( Not ) are performed first. After that, logicalconjunctions ( And ) are performed next. Finally, logicaldisjunctions ( Or ) are performed at the end.

**Question 3: What is the order of operations in Python?**

**Answer 3: **PEMDASis P, E, MD, AS; multiplication and division have the same precedence, and the same applies for addition and subtraction. Further, when a divisionoperatorappears before multiplication, division goes first. Thus, theorder Python operatorsare executed in is governed by theoperatorprecedence, and it follows the same rules.