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Questions tagged [java.util.scanner]

A simple text scanner in the JDK which can parse primitive types and strings using regular expressions.

Use this tag for questions related to the Java API library class java.util.Scanner, a class added to the API in Java 5. The class is, according to the Javadoc:

a simple text scanner which can parse primitive types and strings using regular expressions.

Its source can range from a file, the console, or even a string. (This class replaces the older class java.util.StringTokenizer, which was used prior to Java 5 for the same purpose but has less functionality compared to Scanner).

Important canonical posts with this tag are:

Related tags:

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Scanner is skipping nextLine() after using next() or nextFoo()?

I am using the Scanner methods nextInt() and nextLine() for reading input. It looks like this: System.out.println("Enter numerical value"); int option; option = input.nextInt(); // Read numerical value from input System.out.println("Enter 1st…
blekione
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Scanner vs. BufferedReader

As far I know, the two most common methods of reading character-based data from a file in Java is using Scanner or BufferedReader. I also know that the BufferedReader reads files efficiently by using a buffer to avoid physical disk operations. My…
Mads Mobæk
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How can I read input from the console using the Scanner class in Java?

How could I read input from the console using the Scanner class? Something like this: System.out.println("Enter your username: "); Scanner = input(); // Or something like this, I don't know the code Basically, all I want is have the scanner read an…
Hock3yPlayer
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Scanner vs. StringTokenizer vs. String.Split

I just learned about Java's Scanner class and now I'm wondering how it compares/competes with the StringTokenizer and String.Split. I know that the StringTokenizer and String.Split only work on Strings, so why would I want to use the Scanner for a…
Dave
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Take a char input from the Scanner

I am trying to find a way to take a char input from the keyboard. I tried using: Scanner reader = new Scanner(System.in); char c = reader.nextChar(); This method doesn't exist. I tried taking c as a String. Yet, it would not always work in every…
Ralph
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Using scanner.nextLine()

I have been having trouble while attempting to use the nextLine() method from java.util.Scanner. Here is what I tried: import java.util.Scanner; class TestRevised { public void menu() { Scanner scanner = new Scanner(System.in); …
Taylor P.
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What's the difference between next() and nextLine() methods from Scanner class?

What is the main difference between next() and nextLine()? My main goal is to read the all text using a Scanner which may be "connected" to any source (file for example). Which one should I choose and why?
AnnieOK
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How to read from standard input line by line?

What's the Scala recipe for reading line by line from the standard input ? Something like the equivalent java code : import java.util.Scanner; public class ScannerTest { public static void main(String args[]) { Scanner sc = new…
Andrei Ciobanu
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java.util.NoSuchElementException - Scanner reading user input

I'm new to using Java, but I have some previous experience with C#. The issue I'm having comes with reading user input from console. I'm running into the "java.util.NoSuchElementException" error with this portion of code: payment = sc.next(); //…
fortune
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Why is hasNext() False, but hasNextLine() is True?

Question How is it that for a scanner object the hasNextLine() method returns true while the hasNext() method returns false? Note: Based on the input file, the hasNext() method is returning the result as expected; the hasNextLine() does not seem to…
DRich
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How do I use a delimiter with Scanner.useDelimiter in Java?

sc = new Scanner(new File(dataFile)); sc.useDelimiter(",|\r\n"); I don't understand how delimiter works, can someone explain this in layman terms?
NoMoreErrors
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Scanner issue when using nextLine after nextXXX

I've faced an issue when I'm trying to get the user input using Scanner: import java.util.Scanner; public class Main { public static Scanner input = new Scanner(System.in); public static void main(String[] args) { …
Eng.Fouad
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Reading a .txt file using Scanner class in Java

I am working on a Java program that reads a text file line-by-line, each with a number, takes each number throws it into an array, then tries and use insertion sort to sort the array. I need help with getting the program to read the text file. I am…
user12074577
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Validating input using java.util.Scanner

I'm taking user input from System.in using a java.util.Scanner. I need to validate the input for things like: It must be a non-negative number It must be an alphabetical letter ... etc What's the best way to do this?
bhavna raghuvanshi
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Read CSV with Scanner()

My csv is getting read into the System.out, but I've noticed that any text with a space gets moved into the next line (as a return \n) Here's how my csv starts: first,last,email,address 1, address 2 john,smith,blah@blah.com,123 St.…
coffeemonitor
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