Python Entry 1-1, python1-1

Python Entry 1-1, python1-1
The first python program, the omnipotent 'Hello world'

Python usage, print hello world:

1 # print ('hello world')hello

Hello variable

What is a variable?

Variables are the amount of changes. The core is the word 'change' and 'quantity'. changes are both changing, and the amount is a measure of the state.

How to define variables? Variable name (equivalent to the house number, pointing to the space), equal sign, variable value

   name='Egon'   sex='male'   age=18   level=10

Definition specification of variables:

1. Variable names can only be any combination of letters, numbers, and underscores

2. the first character of the variable name cannot be a number.

3. Keywords cannot be declared as variable names

 

User-program interaction

File Header

#!/usr/bin/env python# -*- coding: utf-8 -*- 

 

Note

Code comments are divided into single-line and multi-line comments.#. You can use three pairs of double quotation marks for multi-line comments.""" """

　　

Input

Input: All input values are saved as strings.

 

 

 

Basic Data Type

Number

Int INTEGER: used for identification: age, ID card number, QQ number, and other integer types

Float floating point: used for identification: decimal type, such as salary, height, and weight

String str string:

Used for identification: descriptive content, such as name, gender, nationality, and race

List

userdata = ['name','passwd']

Used for identification: stores multiple values. For example, a person has multiple hobbies.