import pat.Regex;at the top. To create a regular expression matching object type
Regex r = new Regex("[a-z]+");The string argument to the constructor is the regular expression. To see if this regular expression matches anything in a string, do the following:
Regex r = new Regex("[a-z]+([0-9])"); String m=null,m0=null,s = "some stuff8"; if(r.search(s)) { // match succeeded // store result in String m, // in this case it will contain "stuff8" m = r.substring(); // save the backreference, the thing in ()'s // in m0. m0 = r.substring(0); } else { // match failed }That's basically it. You can now get started programming Regex's in java! There are a few other things you will want to know, such as the
If you follow a pattern element by "+" then your pattern will match 1 or more instances of the pattern. Thus, "a+" matches "aaaa". The "*" matches 0 or more instances of the previous pattern, "?" matches 0 or 1 instances of the previous pattern.
Things in parenthesis are grouped: "(and)+" matches "andandand". Moreover, the substring that matched the part of the text in parenthesis can be pulled out in what is called a backreference. This is the thing that substring(0) mentions.
For more details, see the Regex documentation page. Have fun!