python入门第一步

hello world:

print("hello world!")

变量:

name = "lufeng"
name2 = name
print(name,name2)

三元变量

a,b,c = 1,2,3
d = a if a < b else c
print(d)

python脚本开头标志：

#!/usr/bin/env python3

注释：

#单行注释
'''
这是多行注释
1143
34234
'''
msg ='''
msg的内容
1
2
3
'''

用户输入：

username = input("username:")
password = input("passowrd:")

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

info = '''
---------info of ''' + name + ''' ----
name:''' + age + '''
age: ''' + job + '''
'''
print(info)
##效率低
info2 = '''
---------info of %s ----
name:%s
age:%s
job:%s
''' % (name,name,age,job)
print (info2)

info3 = '''
---------info of {_name} ----
name:{_name}
age:{_age}
job:{_job}
''' .format(_name=name,_age=age,_job=job)
print (info3)

info3 = '''
---------info of {0} ----
name:{0}
age:{1}
job:{2}
''' .format(name,age,job)
print (info3)
## %s --- string %d ---数值型 %f --浮点型 

变量转换

print(type(name))
#强制转换数值型
name = int(input(age:))

密文输入：

#密文；
import getpass
password = getpass.getpass(password:)

#密码输入：
import getpass
_username = 'lufeng'
_password = 'abc123'
username = input("username:")
password = getpass.getpass("password:")
if _username == username and _password == password:
    print("welcome user {name}".format(name=username))
else:
    print("involid username or password")