Definition and method of string

Define methods ：
        s=str()
        s=''
        s=""
        s=""""""
capitalize—— Returns the uppercase of the first character of a string     Variable .capitalize()    
title—— Converts a string to a title and returns         Variable .title()
rlowe—— Converts a string to a lowercase string and returns         Variable .capitalize()
upper—— Converts a string to an uppercase string and returns         Variable .capitalize()
    
    
istitle—— Determine whether the string is a title         Variable .capitalize()
islower—— Determine whether the string is all lowercase         Variable .capitalize()
isupper—— Determine whether the string is all uppercase         Variable .capitalize()
    
isalpha—— Determine whether the string is all alphabetic         Variable .isalpha()
isdigit—— Determine whether the string is all numbers         Variable .isdigit()
isspace—— Judge whether the string is all spaces         Variable .isspace()
isanlum—— Determine whether the string is a valid character         Variable .isanlum()
    
center—— According to the length of the string ( Must be greater than the length of the string itself , The unit is the sign bit ) To center ,fillchar（ Optional parameters ） Default is space           Variable .center(width[,fallchar('')],/)
count—— Count the number of characters         Variable .count('*' | "**")
    
endswith—— Determine whether the string is based on '*** For the end       Variable .endswith('**')
startswith—— Determine whether the string is based on '***' Start       Variable .startswith('**')
find—— Find the first occurrence of a character or string , If there is no return -1       Variable .find('**')
rfind—— Find the position of the first occurrence of a character or string from right to left , If there is no return -1       Variable .rfind('**')​​​​​​​
index—— Find the first position of the character or string from left to right , If it doesn't exist, an error will be reported             Variable .index('**')​​​​​​​
rindex—— Find the first position of the character or string from right to left , If it doesn't exist, an error will be reported           Variable .rindex('**')​​​​​​​
encode—— Convert string to byte (byte) Methods （python3）       Variable .encode('**')
        ①：1 byte （byte） = 8 position （bit）
        ②： stay 16 Bit system （ such as 8086 microcomputer ） 1 word （word）= 2 byte （byte）= 16（bit）

         stay 32 Bit system （ such as win32） 1 word （word）= 4 byte （byte）=32（bit）

         stay 64 Bit system （ such as win64）1 word （word）= 8 byte （byte）=64（bit）
                            *decode—— Byte (byte) Methods to convert to strings