Reading values from a text file and separating into String and double

Question

I am having this error with my code: Exception in thread "main" java.util.InputMismatchException
I know the reason for the error, the entire line is being converted into a String, but I am unsure how of how to fix it. I have tried reading up on Delimiters **Exception in thread "main" java.util.InputMismatchException** How do I use a delimiter in Java Scanner?
but it all sounds too complex for my level of understanding.
My code:

import java.util.*;
import java.io.*;
public class POSmain{   
    public static void main(String[] args)throws Exception {

other code

    //create 3 collections to store input, with scanners to extract input
    Map<String, Double> products = new TreeMap<String, Double>();
    Scanner stock = new Scanner(new File("prices.txt"));

my failed attempt at using a Delimiter

    //Delimiter to remove whitespace
    stock.useDelimiter("\\s*[a-z]\\s");

more code

//populate each collection with while loops
while(stock.hasNext()){
        tempString = stock.nextLine();
        tempdouble = stock.nextDouble();
        products.put(tempString,tempdouble);

    }
    stock.close();

Trying to read this file:

TV          999.99
Table         199 
Bed         499.99
Chair         45.49
Milk    3.00
Butter  2.84
Tomato 0.76
Onion 0.54
Lettuce 1.00
Ham 2.50
Bread 1.75

I am not to change nor delete white spaces from the file. I would be most grateful for any help or advice on how I should extract the values. I am happy to provide more code upon request but it I expect this is all that is required. Thanks again and I appreciate any help I get.

score 3 · Accepted Answer · answered Oct 21 '16 at 06:16

From the looks of your file, your delimeter is either some combination of tabs and spaces (the separating characters between the item name and number), or the newline at the end of each line.

In this case, your delimeter should be \\s+, meaning one or more whitespace characters. So your code should look something like this:

Map<String, Double> products = new TreeMap<String, Double>();
Scanner stock = new Scanner(new File("prices.txt")); 
stock.useDelimiter("\\s+");

while (stock.hasNext()) {
    tempString = stock.nextLine();
    tempdouble = stock.nextDouble();
    products.put(tempString,tempdouble);
}
stock.close();

I tested your input file with code similar to what is above on IntelliJ, and it appears to be working.

Thanks Tim your delimiter worked with my code too. I will study check it up in the API to see how it worked to better understand delimeters. Thanks again. — Liam.C, Oct 21 '16 at 06:23
Need to wait 30 seconds till overflow will allow me to do so — Liam.C, Oct 21 '16 at 06:25

score 0 · Answer 2 · answered Oct 21 '16 at 07:03

The usedelimite() method sets the delimiter of Scanner object.Basically it is used by the Scanner object to tokenize string.It is basically used with dealing the files. for more details on Scanner useDelimiter() method please refer below link,

Scanner in Java

Reading values from a text file and separating into String and double

2 Answers2