Java Lecture 8 Strings in Java | Strings methods

 THE ROYAL GROUP OF PAK

Java Lecture 8 (Strings in Java)

In this Lecture, discuss strings in java. We're explain Strings in java from basic to advance and get command of java Strings methods 

Solution is in the video:

A String variable contains a collection of characters surrounded by double quotes:

Methods:

String Length:

A String in Java is actually an object, which contain methods that can perform certain operations on strings. For example, the length of a string can be found with the length() method:

toUpperCase():

Converts whole string into upperCase characters with toUpperCase() method

toLowerCase():

Coverts whole String into smallCase characters with toLowerCase() method

Finding a Character in a String

The indexOf() method returns the index (the position) of the first occurrence of a specified text in a string (including whitespace):

String Concatenation

The + operator can be used between strings to combine them. This is called concatenation:

You can also use the concat() method to concatenate two strings:

Special Characters

Because strings must be written within quotes, Java will misunderstand this string, and generate an error:

String txt = "We are the so-called "Vikings" from the north.";

The solution to avoid this problem, is to use the backslash escape character.

see escape characters in source code

Watch Lecture 5 now 👇 

This is the source code we learn in lecture 5

// Index of a string starts from 0


// escapCh          Result          Description
/*   \'               '           Single Quote
     \"               "           Double Quote
     \\               \            BackSlash
 */


public class RGP_08_Strings {
    public static void main(String[] args) {
        String greeting = "Good Morning!";
        String info = "This is a Java Course";
        System.out.println(info);

// length()
        System.out.println(info.length());
// toUpperCase()
        System.out.println(info.toUpperCase());
// toLowerCase()
        System.out.println(info.toLowerCase());

// indexOf()
        System.out.println(info.indexOf("i"));
// Concatenation()
        System.out.println(greeting + " " + info);
        System.out.println(greeting.concat(info));

        String str = "C:\\Users\\Zahid\\Videos\\Captures";
        System.out.println(str);

        String text = "It\'s a Pen";
        System.out.println(text);

        String txt1 = "Please locate \"Zahid\" where it occurs";
        System.out.println(txt1);

    }
}