元组的特性（索引、切片、重复、连接、成员操作符、迭代）

（1）索引和切片

users = ('root','westos','redhat')
passwds = ('123','456','789')
print(users[0])
print(users[-1])
print(users[1:])
print(users[:-1])
print(users[::-1])

（2）重复

users = ('root','westos','redhat')
passwds = ('123','456','789')
print(users * 3)

（3）连接

users = ('root','westos','redhat')
passwds = ('123','456','789')
print(passwds + ('012','230'))

（4）成员操作符

users = ('root','westos','redhat')
passwds = ('123','456','789')
print('redhat' in users)
print('redhat' not in users)

（5）迭代

for user in users:
    print(user)

for index,user in enumerate(users):
    print('第%d个用户: %s' %(index+1,user))

for user,passwd in zip(users,passwds):
    print(user,':',passwd)