Operators and Precedence Rules

1
9KB

In Python, operators are special symbols that perform operations on operands (values or variables). Operator precedence determines the order in which these operations are evaluated within an expression. Understanding precedence is essential for writing correct and predictable code.

Precedence Levels:

Python follows the PEMDAS (or BODMAS) order of operations, just like basic math. Here's a breakdown from highest to lowest precedence:

  1. Parentheses (): Expressions within parentheses are evaluated first. You can use parentheses to override the default order or to group subexpressions.
  2. Exponentiation **: This operator performs powers or exponentiation. For example, 2 ** 3 equals 8.
  3. Multiplication and Division (*, /, %): These operators have equal precedence. Multiplication and division are evaluated from left to right. The modulo operator (%) calculates the remainder after a division.
  4. Addition and Subtraction (+, -): Similar to multiplication and division, these operators have equal precedence and are evaluated left to right.

Example:

Python
expression = 2 + 3 * 4 - (10 / 2) ** 2

Following PEMDAS:

  1. Evaluate the expression within parentheses first: (10 / 2) ** 2 = 5 ** 2 = 25
  2. Perform exponentiation: 2 + 3 * 4 - 25
  3. Multiplication: 2 + 12 - 25
  4. Left-to-right addition and subtraction: -11

Associativity:

When multiple operators have the same precedence level, associativity determines the direction of evaluation (left to right or right to left). Almost all operators in Python are left-associative, meaning they are evaluated from left to right. However, the exponentiation operator (**) is an exception - it's right-associative.

Example:

Python
expression = 2 ** 3 ** 2  # Right associativity for **

This is evaluated as 2 ** (3 ** 2), which equals 2 ** 9 or 512.

Tips for Using Operators:

  • Use parentheses liberally to improve code readability and enforce the desired evaluation order, especially in complex expressions.
  • Be mindful of the precedence and associativity rules to avoid unexpected results.
  • If the order of evaluation is unclear, break down the expression into smaller steps or use parentheses for clarity.
Like
2
Suche
Kategorien
Mehr lesen
Computer Programming
Bold Text in HTML
To make text bold in HTML, you can use either the <b> or <strong> element. Both...
Von HTML PROGRAMMING LANGUAGE 2024-08-29 01:49:28 0 9KB
Technology
Ethical Code of Conduct
An ethical code of conduct is a set of principles and guidelines designed to help professionals...
Von ALAGAI AUGUSTEN 2024-07-16 17:00:57 0 9KB
Business
Why Your Business Needs IT Services
Businesses often hesitate to hire IT services, considering them a high-cost investment. However,...
Von ALAGAI AUGUSTEN 2024-07-19 14:20:20 0 16KB
Computer Programming
Class Customization and Operator Overloading
Class customization Class customization allows you to define how a class behaves for...
Ausbildung
Immigration timeline 1849-1924
1849: America’s first anti-immigrant political party, the Know-Nothing...
Von Modern American History 2024-08-02 16:41:54 0 11KB
Tebtalks https://forum.tebtalks.com