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:
- startsWith()
- 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:
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 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 ));
}
} |
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 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" ));
}
} |
Check Whether It Starts With Letter 'S' : true
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