Conversion between Strings and Arrays

As we know that strings are not arrays so the String class also provides methods to convert a string to an array of characters and vice versa. These include

toCharArray();

getChars();

valueOf();

char [] toCharArray (): This method converts the invoking string to an array of individual characters. For example : The statement,

char[] ch = sl.toCharArray();

will convert the string Welcome which is referenced by sl to an array of characters such that ch [0] contains ‘W’, ch [1] contains ‘e’ and so on.

void getChars(int srcBegin, int srcEnd, chsr[] dest, int destBegin): This method copies a substring of the invoking string from index srcBegin to index srcEnd-1 into a character array dest starting from index destBegin. For example: The statement,

char[] txtArray = new char[3];

sl.getChars(3,6,txtArray,O);

will copy characters from the String object slat index position 3 to 5 (i.e. 6 – 1) inclusive, so txtArray[0] will be ‘c’, txtArray[1] will be ‘0’ and txtArray[2] will be ‘m’.

static String valueOf (char [] ch): This method will covert an array of characters to a string. For example : The statements,

char[] ch = {‘W’, ‘E’, ‘L’, ‘C’, ‘0’, ‘M’, ‘E’};

String str String.valueOf(ch);

will return the string Welcome from a character array ch and store the reference in str. There are several versions of valueOf () method that can be used to convert a character and numeric values to strings with different parameter types including in t, long, float, double and char.

Now let us consider a example to show how these work.

public class ConversionMethods 
 { 
          public static void main(String[] args) 
       { 
          
           String s1 = "Welcome" ; 
           char[] txtArray = new char[3]; 
           char [] ch = s1.toCharArray(); 
           for( int i =0; i<ch.length; i++) 
                System.out.println("ch["+i+"] = " +ch[i]); 
                s1.getChars(3,6,txtArray,0); 
                for( int i=0;i<txtArray.length;i++) 
                     System.out.println("txtArray["+i+"] = "+txtArray[i]); 
                     char[] c = {'W','E','L','C','O','M','E'}; 
                     String str = String.valueOf(ch); 
                     System.out.println("str = " + str); 
       } 
 }