Summary of regular operations in Java

Http://www.cnblogs.com/nerxious/archive/2013/01/03/2842910.html

Regular expressions are quite efficient at handling strings.

About the use of regular expressions, more of their own experience, interested can refer to related books

Here are the main things to write about the regular operation method in Java

Example 1: Matching

Import Java.util.scanner;class Demo {public    static void Main (string[] args) {        Scanner sc = new Scanner (system.in) ;        Get input        System.out.print ("Please enter:");        String str = sc.nextline ();        Check (str);    }    private static void Check (String str) {        //Match first bit is 1-9, second bit and later 0-9 (number in 4-10)        String regex = "[1-9][0-9]{4,10}";        /*//Match single character is case-A-Z        String regex = "[A-za-z]";        Match numbers, note the escape character        String regex = "\\d";        Matches a non-numeric        String regex = "\\d";        */                if (str.matches (regex)) {            System.out.println ("Match succeeded"),        } else {            System.out.println ("Match failed");        }    }}

The matches () method in the string class here is used to match

Example 2: Cutting

Import Java.util.scanner;class Demo {public    static void Main (string[] args) {        Scanner sc = new Scanner (system.in) ;        System.out.print ("Please Enter:");        String str = sc.nextline ();        Split (str);    }    private static void Split (String str) {        //matches one or more spaces        string regex = "+";                string[] arr = str.split (regex);                for (String S:arr) {            System.out.println (s);}}    }

Here the split () method in the string class is used to cut by regular expression, returning a string array

Example 3: Replace

Import Java.util.scanner;class Demo {public    static void Main (string[] args) {        Scanner sc = new Scanner (system.in) ;        System.out.print ("Please Enter:");        String str = sc.nextline ();        Replace (str);    }    private static void replace (String str) {        //Match overlapping        string regex = "(.) \\1+ ";        String s = str.replaceall (Regex, "*");        System.out.println (s);    }}

Note that the ReplaceAll has two parameters, one is a regular, the other is a replacement character

Summary of regular operations in Java