Java - Scanning comma delimited double and int values

Question

I'm trying to use Java's Scanner class to scan in double and int values delimited by commas.

The following Scanner input = new Scanner(System.in).useDelimiter("\\D"); can only scan int values separated by ,. e.g. input = 1000,2,3

How do I scan in double and int values separated by , e.g. input = 1000.00,3.25,5 or 100.00,2,3.5?

I tried the following but they don't seem to work:

Scanner input = new Scanner(System.in).useDelimiter(",");
Scanner input = new Scanner(System.in).useDelimiter("\\,");
Scanner input = new Scanner(System.in).useDelimiter("[,]");

Using these seems to hang the code. After entering the example input, System.out.println did not execute for the scanned in variables.

Below is my sample code:

import java.io.*;
import java.util.Scanner;

public class Solution {
  public static void main(String args[] ) throws Exception {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */
    System.out.print("Enter your values: ");
    // Scanner input = new Scanner(System.in).useDelimiter("\\D");
    Scanner input = new Scanner(System.in).useDelimiter(",");
    // Scanner input = new Scanner(System.in).useDelimiter("\\,");
    // Scanner input = new Scanner(System.in).useDelimiter("[,]");

    double investmentAmount = input.nextDouble();
    double monthlyInterestRate = input.nextDouble() / 100 / 12;
    double numberOfYears = input.nextDouble();
    double duration = numberOfYears * 12;

    double futureInvestmentValue = investmentAmount * Math.pow((1 + monthlyInterestRate), duration);
    System.out.println(investmentAmount);
    System.out.println(monthlyInterestRate);
    System.out.println(numberOfYears);
    System.out.println(duration);
    System.out.println("Accumulated value is " + futureInvestmentValue);
  }
}

Solution found

Updating the Scanner line to the following seem to have fixed it:

Scanner input = new Scanner(System.in).useDelimiter("[,\n]");

Your code is working fine for me. What's your input and output? — castletheperson
– castletheperson, Commented Oct 13, 2016 at 18:09
@4castle, my input is 1000.00,3.25,1 all on one line as one input. There's no output as the code hangs after entering the input. I'm on OpenJDK Java 7 — j7an
– j7an, Commented Oct 13, 2016 at 18:27
@eduardo-dennis I would if the code works. It still hangs with input.nextLine(); as how you coded it after the last nextDouble() and entering 1000.00,3.25,1 as the input all on one line. — j7an
– j7an, Commented Oct 14, 2016 at 18:47
@j7an copy and paste my exact code it works just as expected. — Eddie Martinez
– Eddie Martinez, Commented Oct 14, 2016 at 18:49

Dmitry Smorzhok · Accepted Answer · 2016-10-13 18:25:09Z

4

Most likely you have Locale issues and your Scanner tries to parse doubles with comma delimeter, but you set comma as a scanner delimeter. Try the following solution:

Scanner input = new Scanner(System.in)
        .useDelimiter(",")
        .useLocale(Locale.ENGLISH);

This will set doubles delimiter to dot and your comma-separated doubles should work fine.

Be sure to place the comma at the end of input to parse the last value, e.g. 1000.00,3.25,5, (may be even it is the primary reason of your inputs not working)

edited Oct 13, 2016 at 18:25

answered Oct 13, 2016 at 18:17

Dmitry Smorzhok

63511 silver badges21 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

j7an Over a year ago

Thanks for figuring this out. Having the input end with comma works.

Community · Accepted Answer · 2017-05-23 11:48:21Z

0

The issue you faced is because nextDouble() doesn't consume the last line. Try adding an input.nextLine() at the end it should work as expected.

   /* Enter your code here. Read input from STDIN. Print output to STDOUT */
System.out.print("Enter your values: ");
Scanner input = new Scanner(System.in).useDelimiter(",");

double investmentAmount = input.nextDouble();
double monthlyInterestRate = input.nextDouble() / 100 / 12;
double numberOfYears = input.nextDouble();
input.nextLine();
double duration = numberOfYears * 12;

double futureInvestmentValue = investmentAmount * Math.pow((1 + monthlyInterestRate), duration);
System.out.println(investmentAmount);
System.out.println(monthlyInterestRate);
System.out.println(numberOfYears);
System.out.println(duration);
System.out.println("Accumulated value is " + futureInvestmentValue);

Scanner is skipping nextLine() after using next(), nextInt() or other nextFoo() methods

edited May 23, 2017 at 11:48

CommunityBot

11 silver badge

answered Oct 13, 2016 at 18:21

Eddie Martinez

13.9k15 gold badges86 silver badges109 bronze badges

5 Comments

j7an Over a year ago

Yes, I must accept all the input on online. Sorry for not being clear.

j7an Over a year ago

I just realized you ended your input with a comma. I tried that and it worked. If I don't end the input with a comma. It won't work.

Eddie Martinez Over a year ago

@j7an check my edit. You can add an input.nextLine() to fix that issue.

j7an Over a year ago

I've added String x = input.nextLine(); below the last nextDouble() and it still hangs. The issue is that useDelimiter needs to delimit both the comma and the carriage return "[,\n]"

Eddie Martinez Over a year ago

I added the code, it is working for me without the need of the last ,.

Collectives™ on Stack Overflow

Java - Scanning comma delimited double and int values

2 Answers 2

1 Comment

5 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

5 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related