1. Join usage: connect the list to a string according to the custom method
l = ['a','a','a','a']
L1 = ''.join(l) #output is 'aaaa'
L2 = 'b'.join(l) #output is 'abababa'
L3 = '5'.join(l) # output is 'a5a5a5a'
2. Split usage: split the string into a list in a custom way (restored from Example 1)
L2.split('b') #result is ['a', 'a', 'a', 'a']
L3.split('5') #result is ['a', 'a', 'a', 'a']
3. Strip usage: remove the characters at both ends of the character (the default is a space, of course, it can also be placed in parentheses with custom characters), so there are rstrip(), lstrip(), which means to remove the right side and remove the left side
l = '222hello22222222'
l.strip('2') #output is 'hello'
l.rstrip('2') # output is 222hello
l.lstrip('2') #output is hello2222222