What are variables in Python? Introduction to Python variables

The content of this article is to introduce to you what are variables in Python? Python variables. It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.

What are variables?

Concept: A variable is a changing quantity, mainly the words "change" and "quantity" . Change means "change".

#Features: Like other programming languages, variables are the most basic storage unit and are containers used to store data. You can quote a specific value and then directly change the reference

How to define variables?

(1) Define a single variable

Variable name = variable value (Note: The equal sign at this time is equivalent to assignment, and it is in English)

a = 1
print(a) // 输出结果为1

(2) Define constants

respectively

Variable name 1, variable name 2 = variable value 1, variable value 2

1 a,b = 1,2
2 print(a,b) // 1,2

(3) Continuously define variables

Variable name 1, variable name 2 = Variable value

a,b = 2
print(a,b)  //2 2

What is the purpose of variable existence?

(1) Conveniently modify the code

(2) Reduce storage space

#打印3遍  我是一个学生print("我是一个学生");print("我是一个学生");print("我是一个学生");

If you do not use variables to execute this code, you can see the need Printing this text multiple times will not only cause writing trouble, but also take up a lot of space. Using variables will become very simple

#打印3遍  我是一个学生name = "我是一个学生"print(name);print(name);print(name);

Notes on variables and naming rules

(1) Variable names can only be letters , any combination of numbers or underscores, the first character of the variable name cannot be a number

(2) Strictly distinguish between uppercase and lowercase letters, letters can be uppercase or lowercase, but they express different things

(3) A variable name must be assigned a value before it is used, and a variable can only refer to one value

(4) It is best to name the variable name so that readers can directly understand what it expresses meaning, and not too long

(5) Use camel case naming, that is, the first word of the variable name is lowercase, and the first letter of each subsequent word is capitalized

(6) Variable The name cannot be a keyword

Commonly used keywords: and, as, assert, break, class, continue, def, del, elif, else, except, exec, finally, for, from, global , if, import, in, is, lambda, not, or, pass, print, raise, return, try, while, with, yield

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