Mixed String

Java String toCharArray()
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The java string toCharArray() method converts this string into character array. It returns a newly created character array, its length is similar to this string and its contents are initialized with the characters of this string.
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Character.toUpperCase(char ch)
----
char a = 'a';
char upperCase = Character.toUpperCase(a);

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Character.isLetter('c')
Character.isLowerCase('c')

public class Test {

   public static void main(String args[]) {
      System.out.println(Character.isLetter('c'));
      System.out.println(Character.isLetter('5'));
  System.out.println(Character.isLowerCase('c'));
      System.out.println(Character.isLowerCase('C'));
   }
}

output:-
true
false
true
false
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if(Character.isLetter(charmessage[counter]) &&
 Character.isLowerCase(charmessage[counter]))
{
    charmessage[counter] = Character.toUpperCase(charmessage[counter]);
}
================
 String str = "This is what is this world in world";
  String[] strarray = str.split(" ");
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Arrays.sort(ch1);
Arrays.sort(ch2);
if(Arrays.equals(ch1,ch2))
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public StringBuffer deleteCharAt(int index)
----
StringBuffer buff = new StringBuffer("Java lang package");
      System.out.println("buffer = " + buff);

      // deleting character from index 4 to index 9
      buff.delete(4, 9);
      System.out.println("After deletion = " + buff);

      buff = new StringBuffer("xxxx);
      System.out.println("buffer = " + buff);
   
      // deleting character at index 2
      buff.deleteCharAt(2);
      System.out.println("After deletion = " + buff);
==============================================

// create StringBuffer object
        StringBuffer sb = new StringBuffer();

        // 1. append some string values
        sb.append("Google is top search-engine. ");

        // 2. again, append some more string values
        sb.append("To get latest topics on Core Java.");

        // 3. third time, append String-3 and
        // add newline '\n'
        sb.append("\nAnd it can search contents in real-time.");

        // convert StringBuffer to String using toString() method
        String str = sb.toString();

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--Covert char to String
------------------------
char a ='t';
String s = ""+a;
String ss = Character.toString(a);
String sss = String.valueOf(a);
================================================
copyOf()
--------
Syntax:

 copyOf(int[] original, int newLength)
----eg.
public static void main(String args[])
    {
        // initializing an array original
        int[] org = new int[] {1, 2 ,3};

        System.out.println("Original Array");
        for (int i = 0; i < org.length; i++)
            System.out.print(org[i] + " ");

        // copying array org to copy
        int[] copy = Arrays.copyOf(org, 5);

        // Changing some elements of copy
        copy[3] = 11;
        copy[4] = 55;

        System.out.println("\nNew array copy after modifications:");
        for (int i = 0; i < copy.length; i++)
            System.out.print(copy[i] + " ");
    }


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--System.arraycopy()
--
Syntax :

public static void
arraycopy(Object source_arr, int sourcePos,Object dest_arr, int destPos, int len)
---eg.
 public static void main(String[] args)
    {
        int s[] = { 10, 20, 30, 40, 50, 60, 70, 80, 90, 100};
        int d[] = { 15, 25, 35, 45, 55, 65, 75, 85, 95, 105};

        int source_arr[], sourcePos, dest_arr[], destPos, len;
        source_arr = s;
        sourcePos = 3;
        dest_arr = d;
        destPos = 5;
        len = 4;

        // Print elements of source
        System.out.print("source_array : ");
        for (int i = 0; i < s.length; i++)
            System.out.print(s[i] + " ");
        System.out.println("");

        System.out.println("sourcePos : " + sourcePos);
       
        // Print elements of source
        System.out.print("dest_array : ");
        for (int i = 0; i < d.length; i++)
            System.out.print(d[i] + " ");
        System.out.println("");
       
        System.out.println("destPos : " + destPos);
       
        System.out.println("len : " + len);
       
        // Use of arraycopy() method
        System.arraycopy(source_arr, sourcePos, dest_arr,
                                            destPos, len);
       
        // Print elements of destination after
        System.out.print("final dest_array : ");
        for (int i = 0; i < d.length; i++)
            System.out.print(d[i] + " ");
    }
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Object[] obj = list.toArray();//ArrayList to Array
for copying arraylist to array
---------------------------
---------------------------
1.List<Integer> list1 = new ArrayList<Integer>(Arrays.asList(ia));  //copy
2.List<Integer> list2 = Arrays.asList(ia);

import java.util.*;

public class GFG1 {
    public static void main(String[] argv)
        throws Exception
    {

        try {

            // creating Arrays of String type
            String a[] = new String[] { "A", "B", "C", "D" };

            // getting the list view of Array
            List<String> list = Arrays.asList(a);

            // printing the list
            System.out.println("The list is: " + list);
        }

        catch (NullPointerException e) {
            System.out.println("Exception thrown : " + e);
        }
    }
}
Output:
The list is: [A, B, C, D]
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=========================================================

----------------------------------string to char[]
String s1="hello";
char[] ch1 = s1.toCharArray();
----------------------------------to sort char []
Arrays.sort(ch1);
----------------------------------
int value=30;
String s1=String.valueOf(value);
System.out.println(s1+10);
//concatenating string with 10
//o/p :- 3010
----------------------------------
String s1 = "java";
String s2 = "ajav";
StringBuffer sb = new StringBuffer(s2);
int index = sb.indexOf(String.valueOf(c));
sb.deleteCharAt(index);
-------------------------------------
String s2 ="avaj";
StringBuffer sb = new StringBuffer(s2);
int index = sb.indexOf(String.valueOf(c)); --or
int index = sb.indexOf(Character.toString(c));
sb.deleteCharAt(index);
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----------- char array to a string in Java?

class CharArrayToString
{
   public static void main(String args[])
   {
      // Method 1: Using String object
      char[] ch = {'g', 'o', 'o', 'd', ' ', 'm', 'o', 'r', 'n', 'i', 'n', 'g'};
      String str = new String(ch);
      System.out.println(str);

      // Method 2: Using valueOf method
      String str2 = String.valueOf(ch);
      System.out.println(str2);
   }
}
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=================================================
package comparator.Emp;
//When we are not allowed to change Class Employee code (i.e we can't implement Comparable)
//We use comparator Interface.
public class Employee
{
 int empid;
 String name;
 int deptid;
 public Employee(int empid, String name, int deptid)
 {
  super();
  this.empid = empid;
  this.name = name;
  this.deptid = deptid;
 }
 /*@Override
 public String toString() {
  return "Empid=" + empid + ", Name=" + name + ", Deptid=" + deptid;
 }*/


}
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package comparator.Emp;
import java.util.*;
//Sort the Employeee Class using empid -- Use Comparator
public class Emp_Runner {

 public static void main(String[] args)
 {
  Employee emp1  = new Employee(111,"Amit",549);
  Employee emp2  = new Employee(674,"Dinesh",549);
  Employee emp3  = new Employee(352,"Manohar",667);
  Employee emp4  = new Employee(642,"Dilip",889);
  Employee emp5  = new Employee(133,"Govind",667);

  List list = new ArrayList();
  list.add(emp1);
  list.add(emp2);
  list.add(emp3);
  list.add(emp4);
  list.add(emp5);
 
  Comparator comp = new Emp_Comp(); //Comparator is Interface so we can't instanciate it.

  Collections.sort(list,new Emp_Comp());  //call to compare() .... from here

  Iterator itr = list.iterator();
  while(itr.hasNext())
  {
   Employee emp = (Employee) itr.next();
   System.out.println("Empid=" + emp.empid + ", Name=" + emp.name + ", Deptid=" + emp.deptid);
 
  }



 }



}
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package comparator.Emp;

import java.util.Comparator;

public class Emp_Comp implements Comparator<Employee>
{

 @Override
 public int compare(Employee e1, Employee e2)
 {

  if(e1.empid > e2.empid)
  {
   return 1;
  }
  else return
    -1;

 }

}
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