String startswith() Method in Java with Examples

In Java, startWith() method of the String class is present in java.lang package is used to check whether the string starts with a specific prefix. The package view is as follows:

 --> java.lang Package
    --> String Class
         --> startWith() Method   

Variants Of String startsWith() method

There are two variants of the startswith() method that are as follows:

1. startsWith()
2. startsWith(String prefix, int strt_pos)

1. String startsWith() method

This method tests if a string starts with the specified prefix beginning from the first index.

Syntax

public boolean startsWith(String prefix)

Parameters

The prefix to be matched.

Return Type

A boolean value that returns true if the character sequence represented by the argument is a prefix of the character sequence represented by this string else returns false.

Example:

Java

// Java Program to Illustrate startsWith() Method
// of String class

// Importing required classes
import java.util.*;

// Class
class GFG {

    // Main driver method
    public static void main(String[] args)
    {

        // Creating custom string
        String str = new String(
            "GeeksforGeeks is Computer Science Portal");

        // Checking whether string starts with
        // corresponding input string passed
        // using startsWith() method and
        // later storing result in boolean value
        boolean ans1 = str.startsWith("Geeks");
        boolean ans2 = str.startsWith("Computer");

        // Printing the boolean value
        System.out.println(ans1);
        System.out.println(ans2);
    }
}

Output

true
false

2. String startsWith(String prefix, int strt_pos) method

This variant has two arguments and tests if a string starts with the specified prefix beginning a specified index. Here we are passing a starting position to be matched which allows us the flexibility  

Syntax

public boolean startsWith(String prefix, int strt_pos)

Parameters:

• prefix: The prefix is to be matched.
• strt_pos: Start position where to begin looking in the string.

Return Type: A boolean value that returns true if the character sequence represented by the argument is a prefix of the character sequence represented by this string; false otherwise.

Example:

Java

// Java Program to Demonstrate Working of startsWith()
// Method of String Class

// Importing required classes
import java.lang.String;

// Class
public class GFG {

    // Main driver method
    public static void main(String args[])
    {
        // Declaring and initialising custom string
        String Str = new String("Welcome to GeeksforGeeks");

        // Display message
        System.out.print(
            "Check whether string starts with Welcome at pos 11 : ");
        // Testing the prefix using startsWith() method
        System.out.println(Str.startsWith("Welcome", 11));

        // Display message
        System.out.print(
            "Check whether string starts with geeks at pos 11 : ");
        // Testing the prefix using startsWith() method
        System.out.println(Str.startsWith("Geeks", 11));
    }
}

Output

Check whether string starts with Welcome at pos 11 : false
Check whether string starts with geeks at pos 11 : true

Real-Life Example

Now let us look up possible applications seen in daily life. This method can primarily be useful to filter prefixes. For example: filtering phone numbers starting from a number of names starting from a particular letter. The latter one is explained in this article. 

Example

Java

// Java Program to Illustrate startsWith() Method
// As Real-time Scenario

// Importing required classes
import java.util.*;

// Class
public class GFG {

    // Main driver method
    public static void main(String args[])
    {

        // Declaring and initialising a string
        String Str = new String("Sandeep Jain");

        // Testing the prefix using startsWith() method
        System.out.print(
            "Check Whether It Starts With Letter 'S' : ");

        // Printing corresponding boolean value
        System.out.println(Str.startsWith("S"));
    }
}

Output

Check Whether It Starts With Letter 'S' : true

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