Which of these method of class String is used to extract a single character

To extract a single character from a String, you can refer directly to an individual character via the charAt( ) method.

Example 1: Returns the char value at the specified index of this string. The first char value is at index 0.

String str = "Welcome to string handling guide";
char ch1 = str.charAt(0);
char ch2 = str.charAt(5);
char ch3 = str.charAt(11);
char ch4 = str.charAt(20);
System.out.println("Character at 0 index is: " + ch1);
System.out.println("Character at 5th index is: " + ch2);
System.out.println("Character at 11th index is: " + ch3);
System.out.println("Character at 20th index is: " + ch4);

Output:

Character at 0 index is: W
Character at 5th index is: m
Character at 11th index is: s
Character at 20th index is: n

Example 2: Throws IndexOutOfBoundsException - if the index argument is negative or not less than the length of this string.

String str = "Java Guides";
char ch1 = str.charAt(str.length() + 1);
System.out.println("character :: " + ch1);

Output:

Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 12
 at java.lang.String.charAt(String.java:658)
 at com.javaguides.strings.methods.ChatAtExample.charAtExample2(ChatAtExample.java:26)
 at com.javaguides.strings.methods.ChatAtExample.main(ChatAtExample.java:6)

Example 3: How to get the first and last character of the string

String str = "Java Guides";
int strLength = str.length();
// Fetching first character
System.out.println("Character at 0 index is: " + str.charAt(0));
// The last Character is present at the string length-1 index
System.out.println("Character at last index is: " + str.charAt(strLength - 1));

Output;

Character at 0 index is: J
Character at last index is: s

getChars()

If you need to extract more than one character at a time, you can use the getChars( ) method.

It has this general form:

void getChars(int sourceStart, int sourceEnd, char target[ ], int targetStart)

Here, sourceStart specifies the index of the beginning of the substring, and sourceEnd specifies an index that is one past the end of the desired substring. Thus, the substring contains the characters from sourceStart through sourceEnd–1.

The array that will receive the characters is specified by target. The index within the target at which the substring will be copied is passed in targetStart. Care must be taken to assure that the target array is large enough to hold the number of characters in the specified substring.

The following program demonstrates the usage of getChars() method:

class getCharsDemo {
    public static void main(String args[]) {
         String s = "This is a demo of the getChars method.";
         int start = 10;
         int end = 14;
         char buf[] = new char[end - start];
         s.getChars(start, end, buf, 0);
         System.out.println(buf);
    }
}

Here is the output of this program:

demo

getBytes()

There are four versions of getBytes() methods. There is an alternative to getChars( ) that stores the characters in an array of bytes.

byte[] getBytes() - Encodes this String into a sequence of bytes using the platform's default charset, storing the result into a new byte array.

byte[] getBytes(Charset charset) - Encodes this String into a sequence of bytes using the given charset, storing the result into a new byte array.

void getBytes(int srcBegin, int srcEnd, byte[] dst, int dstBegin) - Deprecated.

byte[] getBytes(String charsetName) - Encodes this String into a sequence of bytes using the named charset, storing the result into a new byte array.

Which method is used to extract a single character from a string in Java?

Which of these methods of class string is used extract more than one character?

Which of this method of class String is used to extract a substring from a string object substring () substring () substring () none of the mentioned?

What is use of charAt () method Mcq?