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
Technology
Using the SUM Function in Excel: A Step-by-Step Guide
The SUM function in Excel is a powerful tool used to calculate the total of a range of numbers....
Von Microsoft Excel 2024-09-03 03:17:00 1 12KB
Computer Programming
Setting up a text editor for HTML
Choosing a Text Editor The first step is to select a suitable text editor. There are numerous...
Von HTML PROGRAMMING LANGUAGE 2024-08-13 03:18:39 0 8KB
Computer Programming
Global attributes (id, class, style, title)
Global attributes are attributes that can be applied to any HTML element. They provide additional...
Von HTML PROGRAMMING LANGUAGE 2024-08-15 01:29:55 0 8KB
Ausbildung
Find scholarships and study in the United States
There are countless scholarships available in the United States, offered by various institutions,...
Von Mpatswe Francis 2024-08-31 18:45:10 5 11KB
Wellness
Choosing Kindness in the Face of Anger: A Path to Transformation
Imagine standing at the crossroads of an emotional storm. Someone’s words or actions have...
Von ALAGAI AUGUSTEN 2024-12-18 16:55:54 0 14KB
Talksphare https://talksphare.com