# 1.capitalize -> Change the first character to uppercase
# s = "jack"
# result = s.capitalize()
# print(result)
# 2.casefold -> Compare before string , All changed to the same
# s = 'Jack'
# s2= 'jack'
# ret = s.casefold() == s2
# print(ret)
# 3.center -> Fill both sides of the string
# a="jack"
# ret = a.center(50,'-')
# print(ret)
# 4.expandtabs -> It can be seen as a keyboard tab key
# s = "jack boy"
# ret = s.expandtabs(20)
# print(ret)
# 5.ljust -> Fill left side of string && rjust -> The right side of the string is filled with
# s = "jack"
# ret = s.rjust(20,'-')
# print(ret)
# 6.lower -> All lowercase && upper -> All variable capitals
# s = "hello world"
# ret = s.upper()
# print(ret)
# 7.swapcase -> Case interchangeability
# a = "jACK"
# ret = a.swapcase()
# print(ret)
# 8.title -> Change to title , That is, the first letter of each word is capitalized
# s = "jack"
# ret = s.title()
# print(ret)
# 9.zfill -> Fill in the empty space of the string 0
# s="Jack"
# ret = s.zfill(20)
# print(ret)
# 10.strip() -> Remove the space on both sides && rstrip() -> Remove the right && lstrip() -> Remove the left side
# s = " jack "
# ret = s.strip()
# print(ret)
# 11.format() -> Reference external variables
# msg = "my name is {name}, i am {age} years old. "
# result = msg.format(name="JackMa",age=56)
#
# print(result)
String judgment
# 1.startswith -> Judge initial && endswith -> Judge the tail letter
# a = "Jack"
# s = a.startswith('J')
# print(s)
# 2.isalnum -> Is it a letter or Numbers isalpha -> Is it a letter
# s = "jack123"
# ret = s.isalnum()
# print(ret)
# 3.isidentifier -> Is it legal to make the name of the variable
# s = "1boy"
# ret = s.isidentifier()
# print(ret)
# 4.isnumeric -> Is it a number && Follow isdigit There are some differences
# age=" twenty-five "
# ret = age.isnumeric()
# print(ret)
# 5.isspace -> Is it a space && isprintable -> Whether it can be printed
# ret = ' '.isspace()
# print(ret)
# istitle -> Determine whether the initial is capitalized && isupper -> Judge whether the letters are capitalized
# s = "Hello"
# ret = s.istitle()
# print(ret)
