The Java Scanner nextFloat() method scans the next token of the input as a float. This method will throw InputMismatchException if the next token cannot be translated into a valid float value as described below. If the translation is successful, the scanner advances past the input that matched.
DeclarationFollowing is the declaration for java.util.Scanner.nextFloat() method
public float nextFloat()Parameters
NA
Return ValueThis method returns the float scanned from the input
ExceptionInputMismatchException − if the next token does not match the Float regular expression, or is out of range
NoSuchElementException − if the input is exhausted
IllegalStateException − if this scanner is closed
The following example shows the usage of Java Scanner nextFloat() method to scan the next token as Float. We've created a scanner object using a given string. Then we checked each token to be Float and printed otherwise Not Found is printed along with scanned token. In the end scanner is closed using close() method.
package com.tutorialspoint; import java.util.Scanner; public class ScannerDemo { public static void main(String[] args) { String s = "Hello World! 3 + 3.0 = 6"; // create a new scanner with the specified String Object Scanner scanner = new Scanner(s); while (scanner.hasNext()) { // check if the scanner's next token is a Float if(scanner.hasNextFloat()){ // print what is scanned System.out.println("Found: " + scanner.nextFloat()); } else { System.out.println("Not Found: " + scanner.next()); } } // close the scanner scanner.close(); } }Output
Let us compile and run the above program, this will produce the following result −
Not Found: Hello Not Found: World! Found: 3.0 Not Found: + Found: 3.0 Not Found: = Found: 6.0Getting Next Token as Float of a Scanner on User Input Example
The following example shows the usage of Java Scanner nextFloat() method to scan the next token as Float. We've created a scanner object using System.in class. Then we checked each token to be Float and printed otherwise Not Found is printed along with scanned token. In the end scanner is closed using close() method.
package com.tutorialspoint; import java.util.Scanner; public class ScannerDemo { public static void main(String[] args) { // create a new scanner with System Input Scanner scanner = new Scanner(System.in); while (scanner.hasNext()) { // check if the scanner's next token is a Float if(scanner.hasNextFloat()){ // print what is scanned System.out.println("Found: " + scanner.nextFloat()); } else { System.out.println("Not Found: " + scanner.next()); } } // close the scanner scanner.close(); } }Output
Let us compile and run the above program, this will produce the following result − (where we've entered 3.0.)
3.0 Found: 3.0Getting Next Token as Float of a Scanner on Properties File Example
The following example shows the usage of Java Scanner nextFloat() method to scan the next token as Float. We've created a scanner object using a file properties.txt. Then we checked each token to be Float and printed otherwise Not Found is printed along with scanned token. In the end scanner is closed using close() method.
package com.tutorialspoint; import java.io.File; import java.io.FileNotFoundException; import java.util.Scanner; public class ScannerDemo { public static void main(String[] args) throws FileNotFoundException { // create a new scanner with a file as input Scanner scanner = new Scanner(new File("properties.txt")); while (scanner.hasNext()) { // check if the scanner's next token is a Float if(scanner.hasNextFloat()){ // print what is scanned System.out.println("Found: " + scanner.nextFloat()); } else { System.out.println("Not Found: " + scanner.next()); } } // close the scanner scanner.close(); } }
Assuming we have a file properties.txt available in your CLASSPATH, with the following content. This file will be used as an input for our example program −
Hello World! 3 + 3.0 = 6Output
Let us compile and run the above program, this will produce the following result −
Not Found: Hello Not Found: World! Found: 3.0 Not Found: + Found: 3.0 Not Found: = Found: 6.0
java_util_scanner.htm
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