Python for Beginners: Variable Basics — Definition, Assignment, and Usage

A variable is a "container" for storing data in programming, used to flexibly store and modify information (such as age, weight) and avoid repeatedly writing specific numerical values. In Python, variables are defined directly using "variable name = value" (e.g., age = 18), without type declaration; the assignment determines the type (dynamic typing). Variable naming must follow rules: it can only contain letters, numbers, and underscores, cannot start with a number, cannot use keywords (e.g., if), and is case-sensitive (age ≠ Age). When using, variables are printed by name (print(age)) or involved in calculations (e.g., x + y). The variable type changes with the last assignment (e.g., after a = 10, a = "Python"). Precautions: A variable must be assigned before use; variable names should be meaningful (e.g., student_count instead of sc); avoid repeated assignment that overwrites the original value. Variables are a core tool in Python; mastering their definition, naming, and usage enables efficient data processing.