Regex
Regular Expression A regular expression (shortened as regex or regexp), sometimes referred to as rational expression, is a sequence of characters that specifies a match pattern in text. Usually such patterns are used by string-searching algorithms for “find” or “find and replace” operations on strings, or for input validation. Basic rule for Regex Quantifier(限定符):only for one character ?: means the character show up before ? once or zero, for example:...