Regular Expressions in Python
Regular Expressions: A regular expression (or RE) specifies a set of strings that matches it; the functions in this module let you check if a particular string matches a given regular expression. Regular expressions can contain both special and ordinary characters. Ordinary Characters: Most ordinary characters, like 'A' , 'a' , or '0' , are the simplest regular expressions; they simply match themselves. Special Characters: Some characters, like '|' or '(' , are special. Special characters either stand for classes of ordinary characters or affect how the regular expressions around them are interpreted. The special characters are:: a) ' . '(Dot): this matches any character except a newline b) '^': (Caret.) Matches the start of the string c) '$': Matches the end of the string or just before the newline at the end of the string d) '*': It causes the resulting RE to match 0 or m