Day01的课程要点记录
详细教程地址：金角大王 - Day1 Python基础1 | 银角大王 - 初始Python
一、我能学会吗？
Can I become a great coder?
Yes - in time. The best coders go through several phases on their programming journey:
-
The "I know nothing" phase - 起始阶段
Everything is new, nothing is easy. -
The "it's starting to make sense" phase -
You're written a few programs and are making fewer mistakes. -
The "I'm invincible" phase - 第三个月到第五个月
Your confindence matches your competence. No challenge seems to difficult. -
The "I know nothing" phase,part II - 项目实战
The sudden realization that development is infinitely more complex and you begin to doubt your own abilities. -
The "I know a bit and that's OK" phase - 四、五年开发经验
You have decent coding skills but recognize your limitations and can find solutions to most problems (even if that means hiring another developer).
二、2与3的选择
语法区别
#2.x
print “hello world”
#3.x
print("hello")
2.x 汉字需要声明
#_*_coding:utf-8_*_
三、Python安装
- Windows
1、下载安装包
https://www.python.org/downloads/
2、安装
默认安装路径：C:\python27
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
无需安装，原装Python环境
ps：如果自带2.6，请更新至2.7
四、Python入门
- Hello World程序
print("Hello World!")
- 在Linux下运行
print("Hello World!")
print("Hello Again.")
print("hello again \ntwice") #\n 为换行
#检查是否有可执行权限
ll hello.py (Mac: ls -slh)
#添加可执行权限
chmod +x hello.py #方法1
chmod 755 hello.py #方法2
#指定解释器 - 在文件第一行添加
#!/usr/bin/python (不推荐)
#!/usr/bin/env python (推荐)
- 注意点
- 带有引号的（‘ "），无论几个，都代表是字符串。
- 命名推荐两种方式：“MyName” or “my_name”
五、字符编码
1.指定字符集
#!/usr/bin/env python #指定解释器
# -*- coding: utf-8 -*- #指定字符集
print "你好，世界"
2.设置模版
[Settings] --> [Editor] --> [File and Code Templates] --> [Python Script]
3.注释
单行注释：# 被注释内容
多行注释：""" 被注释内容 """ （三个引号，单引号双引号均可。）
六、变量
1.声明变量
name = "Will"
上述代码声明了一个变量，变量名为： name，变量name的值为："Will"
2.变量定义的规则
- 变量名只能是 字母、数字或下划线的任意组合
- 变量名的第一个字符不能是数字
- 以下关键字不能声明为变量名
['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']
3.变量的赋值
name = "Will Wang"
name2 = name #name2指向name所指向的"Will Wang"
print(name, name2)
name = "Jack" #内存中开辟新地址保存为“Jack”
print(name, name2)
print("What is the value of name2 now?\n" + name2)
七、用户输入
1. 输入用户名
- 2.x
name = raw_input("Please input your name:")
print("Welcome," + name)
- 3.x
name = input("Please input your name:")
print("Welcome," + name)
2. 格式化字符串
name = input("Please input your name:")
age = int(input("Please input your age:")) #convert str to int
job = input("Please input your job:")
msg = '''
Information of user %s:
Name: %s
Age : %d
Job : %s
'''%(name, name, age, job)
print(msg)
Ctrl + D 复制当前行
占位符：%s = string 字符，%d = digital 数字，%f = 小数、浮点
input 默认输入的是字符串，数字需要用int()转换
3. 常用模块初识
- getpass 输入密码
#Pycharm下不可用，仅限于Linux命令行或Windows的CMD
import getpass
username = input("username:")
password = getpass.getpass("password:")
print(username, password)
- OS 调用系统命令
#!/usr/bin/env python
# -*- coding: utf-8 -*-
import os
os.system("df -h") #调用系统命令
import os
os.system("df")
os.mkdir("yourDir")
cmd_res = os.popen("df -h").read() #读取内存中的显示值并打印
4. 自己写个模块
python tab补全模块
- for Mac
import sys
import readline
import rlcompleter
if sys.platform == 'darwin' and sys.version_info[0] == 2:
readline.parse_and_bind("bind ^I rl_complete")
else:
readline.parse_and_bind("tab: complete") # linux and python3 on mac
for mac
- for Linux
#!/usr/bin/env python
# python startup file
import sys
import readline
import rlcompleter
import atexit
import os
# tab completion
readline.parse_and_bind('tab: complete')
# history file
histfile = os.path.join(os.environ['HOME'], '.pythonhistory')
try:
readline.read_history_file(histfile)
except IOError:
pass
atexit.register(readline.write_history_file, histfile)
del os, histfile, readline, rlcompleter
for Linux
自己写的tab.py模块只能在当前目录下导入，如果想在系统的任何一个地方都使用，要把这个tab.py放到python全局环境变量目录里。
一般都放在一个叫Python/2.7/site-packages目录下。
这个目录在不同的OS里放的位置不一样，用print(sys.path)可以查看python环境变量列表。
八、表达式if...else
1. 用户登录验证
- 判断用户名和密码
user = "will"
passwd = "wang1234"
username = input("username:")
password = input("password:")
if user == username:
print("Username is correct...")
if passwd == password:
print("Welcome back, %s" %username)
else:
print("Password is not invaild...")
else:
print("Guess it again, %s" %username)
#优化v1
user = "will"
passwd = "wang1234"
username = input("username:")
password = input("password:")
if user == username and passwd == password: # 用and同时判断username和password
print("Welcome back, %s" %username)
else:
print("Invalid username or password...")
2. 猜年龄
age = 31
guess_num = int(input("Please input the number you guess:"))
if guess_num == age:
print("Congratulations! You got it!")
elif guess_num > age:
print("Think it smaller.")
else:
print("Think it bigger.")
九、循环
1. for循环
- 最简单的循环10次
for i in range(10):
print("loop:", i )
- 年龄游戏
age = 31
for i in range(10):
guess_num = int(input("Please input the number you guess:"))
if guess_num == age:
print("Congratulations! You got it!")
break #停止往后继续走，跳出整个loop
elif guess_num > age:
print("Think it smaller.")
else:
print("Think it bigger.")
- 年龄游戏（尝试3次）
age = 31
for i in range(10):
if i < 3:
guess_num = int(input("Please input the number you guess:"))
if guess_num == age:
print("Congratulations! You got it!")
break #停止往后继续走，跳出整个loop
elif guess_num > age:
print("Think it smaller.")
else:
print("Think it bigger.")
else:
print("You have tried too many times, good bye.")
break
- 年龄游戏（每尝试3次，询问是否继续）
age = 31
counter = 0 #自己的计数器
for i in range(10):
if counter < 3:
guess_num = int(input("Please input the number you guess:"))
if guess_num == age:
print("Congratulations! You got it!")
break #停止往后继续走，跳出整个loop
elif guess_num > age:
print("Think it smaller.")
else:
print("Think it bigger.")
else:
continue_confirm = input("Do you want try it again? type y to continue : ")
if continue_confirm == "y":
counter = 0
continue #跳出本次循环
else:
print("bye")
break
counter += 1
2. while循环
- 年龄游戏
age = 31
count = 0
while True:
guess_num = int(input('Please input your guees number:'))
if guess_num == age:
print('Yes, you got it!')
break
elif guess_num < age:
print('Please think it bigger!')
else:
print('Please think it smaller!')
- 年龄游戏（尝试3次）
age = 31
count = 0
while count < 3:
guess_num = int(input('Please input your guess number:'))
if guess_num == age:
print('Yes, you got it!')
break
elif guess_num < age:
print('Please think it bigger')
else:
print('Please think it smaller!')
count += 1
else:
print('You have trid too many times. Byebye')
- 年龄游戏（每尝试3次，询问是否继续）
age = 31
count = 0
while count < 3:
guess_num = int(input('Please input your guess number:'))
if guess_num == age:
print('Yes, you got it!')
break
elif guess_num < age:
print('Please think it bigger')
else:
print('Please think it smaller!')
count += 1
if count == 3:
continue_confirm = input('Do you want keep tring?')
if continue_confirm != 'n': # !=是不等于
count = 0
十、作业
作业一：博客
作业二：编写登陆接口
- 输入用户名密码
- 认证成功后显示欢迎信息
- 输错三次后锁定
作业三：多级菜单
- 三级菜单
- 可依次选择进入各子菜单
- 所需新知识点：列表、字典
- 流程图：www.processon.com
- Readme.md
- test.md
