Learn about the regular expressions in programming with examples explained in python. link : https://automatetheboringstuff.com/chapter7/ summary The ? matches zero or one of the preceding group. The * matches zero or more of the preceding group. The + matches one or more of the preceding group. The {n} matches exactly n of the preceding group. The {n,} matches n or more of the preceding group. The {,m} matches 0 to m of the preceding group. The {n,m} matches at least n and at most m of the preceding group. {n,m}? or *? or +? performs a nongreedy match of the preceding group. ^spam means the string must begin with spam . spam$ means the string must end with spam . The . matches any character, except newline characters. \d ,...