Python自动化之语法基础

1 第一个程序 hello world

在Linux环境下执行 vim hello.py

#!/usr/bin/env python     #指定解释器
print("hello world")

运行Python程序

Python hello.py

2 变量和字符编码

变量定义规则

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']

变量赋值问题

name = "me"

name2 = name

print(name,name2)

name = "me_new"

print(name,name2)

执行结果

me me
me_new me

3 字符编码

3.1 Python里面的中文写法

在Python3下是支持中文的

print ("你好中国")

Python2的写法

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

print "你好中国"

python如何使用注释

单行注释 #后面加被注释的内容

多行注释 可以在每行前面加#或者使用'''被注释的内容'''　　

4 用户输入

输入名字并打印出来

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

name = input("input your name:")
print(name)

getpass模块初始

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

import getpass

# 将用户输入的内容赋值给 name 变量
password = getpass.getpass("input password：")

# 打印输入的内容
print(password)

4.1 3种格式化输出

第一种%格式化输出

#!/usr/bin/env python
#Author:wushipeng

name = input("name:")
job = input("job:")
salary = input("salary:")

info ='''
--------info of %s----------
name:%s
job:%s
salary:%s
''' % (name, name, job, salary)

info1 ='''
--------info of {name}----------
name:{name}
job:{job}
salary:{salary}
'''.format(name=name, job=job, salary=salary)

结果

name:wu
job:it
salary:3000

--------info of wu----------
name:wu
job:it
salary:3000

第二种format格式化输出

#!/usr/bin/env python
#Author:wushipeng

name = input("name:")
job = input("job:")
salary = input("salary:")

info1 ='''
--------info of {name}----------
name:{name}
job:{job}
salary:{salary}
'''.format(name=name, job=job, salary=salary)

结果

name:wu
job:it
salary:3000

--------info of wu----------
name:wu
job:it
salary:3000

第三种format数字代指变量

#!/usr/bin/env python
#Author:wushipeng

name = input("name:")
job = input("job:")
salary = input("salary:")

info2 = '''
--------info of {0}----------
name:{0}
job:{1}
salary:{2}
'''.format(name, job, salary)

结果

name:wu
job:it
salary:3000

--------info of wu----------
name:wu
job:it
salary:3000

5 表达式if ... else

猜年龄案例

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

age = 28
while True:
age_new = int(input("input you age:"))
if age_new > age:
print("it's bigger than age")
elif age_new < age:
print("it's smaller than age")
else:
print("you guess it")
break

while实现限制5次，5次之后直接结束

age = 28
count = 0
while True:

age_new = int(input("input you age:"))
if age_new > age:
print("it's bigger than age")
elif age_new < age:
print("it's smaller than age")
else:
print("you guess it")

count += 1
if count == 5:
break

6 for循环

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

for i in range(10):
print(i)

结果：
0
1
2
3
4
5
6
7
8
9

猜年龄只限制输入5次

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

age = 28
for i in range(5):
age_new = int(input("input you age:"))
if age_new > age:
print("it's bigger than age")
elif age_new < age:
print("it's smaller than age")
else:
print("you guess it")
break