Python Learning Notes (i) Introduction overview

Class 1

First, Introduction

Python: scripting language, interpreted language

Indentation is a very important sign of the Python language.

Python3 is the future development trend

Second, installation

Windows:

1. Download the installation package:

https://www.python.org/downloads/

    2、安装：


    默认安装路径：C:\python2.7


    3、配置环境变量


    【右键计算机】--》【属性】--》【高级系统设置】--》【高级】--》【环境变量】--》【在第二个内容框中找到 变量名为Path 的一行，双击】 --> 【Python安装目录追加到变值值中，用 ； 分割】

    如：原来的值;C:\python27，切记前面有分号

linux & mac


    系统默认已经安装

Third, the first procedure

　　print("hello world")

    指定解释器：如果想要类似于执行shell脚本一样执行python脚本，例： ./hello.py ，那么就需要在 hello.py 文件的头部指定解释器，如：

    #!/usr/bin/env python


　　执行前需给予 hello.py 执行权限，chmod 755 hello.py

Iv. Variables & Character encodings

Variable name definition rules:

　　1、Variable names can only be any combination of letters, numbers, or underscores

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

3. Variable name cannot be a keyword

4, the variable name can not contain spaces and special characters (_ except)

Code:-*-coding:utf-8-*-

Five, module

Python has a rich and powerful library of standards and third-party libraries, which can be implemented in a non-language comparable capacity.

There is an unknown table here, and then record it after learning.

Python Learning Notes (i) Introduction overview