常用：分割、长度、索引、切片
r = (1,2,3,4,5)#只读列表元组
name = "liangml"
strip
username = input("user:")
if username.strip() == "liangml":#strip可以将输入前后的空格都换掉
print("welcome")
split
names = "liangml","tom","jack"
name2 = names.split(",")#split是names拆分开来（得到一个列表）
print("|".join(name2))#join是将name2结果以|形式合并到一起
print("" in name)#有没有空格
capitalize
print(name.capitalize())#capitalize是将名字的首字母大写
format
#format字符串两种赋值方式
msg = "Hello,{name},It's been a long {age} since last time sopke...."
#msg2 = msg.format(name="zhangsan",age=111)
#print(msg2)
msg2 = "lisi{0},dddd{1}"
print(msg2.format("liangml",22))
center
print(name[2:4])
print(name.center(40,"-"))#center可以指定长度,将字符串两边的长度均匀的分开
find
print(name.find("a"))#find查找赋值中有几个包含字符串
isdigit
age = input("your age:")
if age.isdigit():#isdigit判断他是否为数字
age = int(age)
else:
print("invalid data type")
isalnum
name = "liangml!dfs"
print(name.isalnum())#不容许复制里面有特殊字符
endswith、startswith
print(name.endswith("dfsd"))
print(name.startswith("dfsfds"))
upper、lower
print(name.upper().lower())#upper赋值全部大写，lower全部变小
