Java String length() Method
Introduction
The length()
method in Java is a fundamental tool for working with strings. It simply tells you how many characters are present within a string. Think of it like counting the letters in your name or words in a sentence – that's essentially what this method does.
Syntax
public int length()
Parameters
Parameter |
Description |
None |
This method doesn't accept any input parameters. |
Return Value
The length()
method returns an integer representing the number of characters in the string.
Examples
Example 1: Basic String Length
Let's start with a simple example to illustrate how length()
works. We'll create a string and then use length()
to find out its length.
public class StringLengthExample1 {
public static void main(String[] args) {
String myString = "Hello, World!";
int stringLength = myString.length();
System.out.println("The length of the string is: " + stringLength);
}
}
The length of the string is: 13
In this example, `myString` contains "Hello, World!". The length()
method returns 13 because there are thirteen characters in the string (including the space and the exclamation mark).
Example 2: Empty String
What happens when we use length()
on an empty string? Let's find out.
public class StringLengthExample2 {
public static void main(String[] args) {
String emptyString = "";
int length = emptyString.length();
System.out.println("The length of the string is: " + length);
}
}
The length of the string is: 0
As expected, an empty string has a length of zero.
Example 3: String with Unicode Characters
Java strings can contain Unicode characters. Let's see how length()
handles those.
public class StringLengthExample3 {
public static void main(String[] args) {
String unicodeString = "你好世界"; // Chinese for "Hello World"
int length = unicodeString.length();
System.out.println("The length of the string is: " + length);
}
}
The length of the string is: 4
Even though '你好世界' looks like four characters, each character in this string is represented by one code point. The `length()` method returns the number of code points (characters) in the string.
Example 4: String Derived from User Input
Often you’ll get strings from user input – let's see how to use `length()` with that kind of data.
import java.util.Scanner;
public class StringLengthExample4 {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter a string: ");
String userInput = scanner.nextLine();
int length = userInput.length();
System.out.println("The length of your input is: " + length);
scanner.close();
}
}
This example prompts the user to enter a string, then calculates and prints its length.