Common instances and functions of Java strings

• string comparison

String Functions CompareTo (String), Comparetoignorecase (String), and CompareTo (object string) to compare two strings and return the difference between the first letter of ASCII in a string.

 Public class stringcompareemp{   publicstaticvoid  main (String args[]) {      = " Hello World ";       = "Hello World";       = str;       System.out.println (Str.compareto (anotherstring));      System.out.println (Str.comparetoignorecase (anotherstring));   // Ignore Case       System.out.println (Str.compareto (objstr.tostring ()));}   }

• String Lookup

The String class's IndexOf () method finds where a substring appears in a string, such as where the return string appears (the first bit is 0), and if no return-1 exists.

 Public class searchstringemp {   publicstaticvoid  main (string[] args) {      = " Google Java Taobao ";       int intindex = strorig.indexof ("Java");       if (Intindex = =-1) {         System.out.println ("string Java not Found");      } Else {         System.out.println ("Java string position" + intindex);    }}}

• Find where the string last occurred

The String function Strorig.lastindexof (Stringname) to find the substring stringname where the strorig appears.

 Public class searchlaststring {   publicstaticvoid  main (string[] args) {      = " Hello World, Hello Runoob ";       int lastIndex = strorig.lastindexof ("Hello");       if (LastIndex = =-1) {         System.out.println ("string not Found");      } Else {         System.out.println ("where the string last appears:" + LastIndex);}}}   

• Remove one character from a string

By using the String function substring () function to remove one character from a string, we encapsulate the function in the Removecharat function.

 Public class Main {   publicstaticvoid  main (String args[]) {      = ' This is Java ' ;       3));   }     Public Static int POS) {      return s.substring (0, POS) + s.substring (pos + 1);}   }

• String substitution

The Replace method of the Java string class can replace characters in a string.

 Public class Test {    publicstaticvoid  Main (string args[]) {            string str= " Hello World,hello Java. " ;            System.out.println (str.replace (' H ', ' W ')); Replace All            System.out.println (Str.replacefirst ("He", "Wa"));//Replace the first encountered            System.out.println ( Str.replaceall ("He", "Ha")); Replace All       }}

• String inversion

The inverse function of Java reverse () can be string reversed.

 Public class Test {    publicstaticvoid  Main (string args[]) {            string str= " Hello Java. " ;             New StringBuffer (str). reverse (). toString ();            System.out.println ("string reversal before:" +str);            System.out.println ("After string reversal:" +reverse);}       }

• String segmentation

The split (string) method splits a string into an array by specifying a delimiter.

 Public classTest { Public Static voidMain (String args[]) {string str= "Www-baidu-com";            String[] temp; String Delimeter= "-";//Specify delimitertemp = Str.split (delimeter);//Split String//normal for Loop             for(inti = 0; i < temp.length; i++) {System.out.println (temp[i]); System.out.println (""); } System.out.println ("----java for Each loop output method-----"); String str1= "Www.baidu.com";            String[] Temp1; String Delimeter1= "\\.";//Specifies the delimiter, the. Number needs to be escapedTemp1 =Str1.split (Delimeter1);  for(String x:temp1) {System.out.println (x); System.out.println (""); }           }}

• String lowercase to uppercase

The string toUpperCase () method converts the strings from lowercase to uppercase.

String str = "string Runoob";         = Str.touppercase ();

• Tests whether two string regions are equal

 Public classstringregionmatch{ Public Static voidMain (string[] args) {String first_str= "Welcome to Microsoft"; String Second_str= "I work with Microsoft"; BooleanMatch1 =First_str. Regionmatches (One, Second_str, 12, 9); BooleanMATCH2 =First_str. Regionmatches (true, one, Second_str, 12, 9);//The first parameter, True, indicates that the case difference is ignoredSYSTEM.OUT.PRINTLN ("Case-sensitive return value:" +match1); System.out.println ("Case-insensitive return value:" +MATCH2); }}

first_str.regionmatches (One, Second_str, 9) indicates that the first_str string starts with the 11th character "M" and second_str The 12th character "M" of the string begins to be compared, comparing 9 pairs of characters, and the result is false because the string is case-sensitive.

If the first parameter is set to True, the case difference is ignored, so true is returned.

• Connection string

Use the "+" operator and the Stringbuffer.append () method to concatenate strings.

 Public classStringconcatenate { Public Static voidMain (string[] args) {LongStartTime =System.currenttimemillis ();  for(inti=0;i<5000;i++) {String result= "This is" + "testing the" + "difference" + "between" + "String" + "and" + "StringBuffer"; }        LongEndTime =System.currenttimemillis (); System.out.println ("String Connection" + "-using the + operator:" + (Endtime-starttime) + "MS"); LongStartTime1 =System.currenttimemillis ();  for(inti=0;i<5000;i++) {stringbuffer result=NewStringBuffer (); Result.append ("This is"); Result.append ("Testing the"); Result.append ("Difference"); Result.append ("Between"); Result.append ("String"); Result.append ("and"); Result.append ("StringBuffer"); }        LongEndTime1 =System.currenttimemillis (); System.out.println ("String Connection" + "-using StringBuffer:" + (ENDTIME1-STARTTIME1) + "MS"); }}

Output:

String connection-using the + operator:0-using stringbuffer:42 ms

Common instances and functions of Java strings