m = re.search(pattern,string) Search the entire string until a matching substring is found
m = re.match(pattern,string) Check whether the string conforms to the regular expression from the beginning, it must match from the first character of the string
str = re.sub(pattern,replacement,string)Use the regular transformation pattern to search in the string, and replace the searched string with another string replacement. Return the replaced string
re.split() Split string according to regular expression, put all substrings after splitting in a table and return
re.findall() Search for strings based on regular expressions, put all matching substrings in a table and return