元组，字符串的基础

元组，字符串，

'''a=(1,2,3,4,56,)
type(a)
print(type(a)) #元祖就是不可变列表
'''

'''username=input("username:")
if username.strip()=="spencer": #语句能够让输入的内容多按空格：移除空白
    print("welcome")
'''

'''names="jack,alex,spencer,tony"
name1=names.split(",") #切分
print(name1)
name2=(":".join(name1)) #合并
print(name2)
print(":".join(name1))
'''

'''msg="if want{0}, then we will{1}"
msg1=msg.format(111,222)
print(msg1)
'''

'''name="spencersun"
print(name[2:4])
print(name.center(50,"~"))
'''

username=input("name:")
if username.isdigit():
    username=int(username)
else:
    print("invalid")