Understanding Regular Expressions
Will discuss about basic regular expression in three stages. Stage 1 Symbol Explanation ^ Start of string $ End of string . Any single character + One or more character \ Escape Special characters ? Zero or more characters Input exactly match with “abc” var A = / ^ abc $ /; Input start with “abc” var B = / ^ abc/; Input end with “abc” var C = /abc $ /; Input “abc” and one character allowed Eg. abcx var D = / ^ abc . $ /; Input “abc” and more than one character allowed Eg. abcxy var E = / ^ abc . + $ /; Input exactly match with “abc.def”, cause (.) escaped var F = / ^ abc \ . def $ /; Passes any characters followed or not by “abc” Eg. abcxyz12.... var G = / ^ abc . + ? $ / Stage 2 Char Group Explanation [abc] Should match any single of character [