Learning Python from Scratch: How to Use if-else Conditional Statements? A Practical Guide with Examples

The if-else conditional statement in Python is used to perform different operations based on conditions, addressing complex scenario judgment requirements (such as determining if a number is positive or negative, or whether a score is passing, etc.). Key syntax notes include adding a colon after the condition, using indentation to denote code blocks, and condition expressions that include comparison operators like >, <, and ==. Scenarios are categorized into three types: 1. Single condition execution uses if (e.g., checking if a number is greater than 5); 2. Binary choice uses if-else (e.g., determining if a score is passing); 3. Multi-condition sequential judgment uses if-elif-else (e.g., grade classification, where the first satisfied condition takes precedence). Key points to avoid: missing colons, indentation errors, improper condition order (e.g., checking lower scores first may prevent higher scores from being recognized), and using == instead of = for comparison operators. Once mastered, it enables flexible implementation of conditional judgment and is a core tool for Python's logical control.