String Arrays not returning expected value

Question

I'm very new to Java but this has had me stumped for the last half an hour or so. I'm reading in lines from a text file and storing them as String Arrays. From here I'm trying to use the values from within the arrays to be used to initialise another class I have. To initialise my Route class (hence using routeName) I need to take the first value from the array and pass it as a string. When I try to return s[0] for routeName, I'm given the last line of from my text file. Any ideas on how to fix this would be greatly appreciated. I'm in the process of testing still so thats why my code is barely finished.

My text file is as follows.

66

Uq Lakes, Southbank

1,2,3,4,5

2,3,4,5,6

and my code:

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


public class Scan {

    public static void main(String args[]) throws IOException {

        String routeName = "";
        String stationName = " ";
        Scanner timetable = new Scanner(new File("fileName.txt"));
        while (timetable.hasNextLine()) {
            String[] s = timetable.nextLine().split("\n");
            routeName = s[0];

        }
        System.out.println(routeName);
    }

}

score 1 · Answer 1 · edited May 23 '17 at 10:25

Scanner.nextLine() returns a single line so splitting by '\n' will always give a single element array, e.g.:

timetable.nextLine().split("\n"); // e.g., "1,2,3,4,5" => ["1,2,3,4,5"]

Try splitting by the ',' instead, e.g.:

timetable.nextLine().split(",");  // e.g., "1,2,3,4,5" => ["1", "2", "3", "4", "5"]

NOTE: If you are intending for the array to contain individual lines, then check out this SO post.

Scanner s = new Scanner(new File(filename));
List<String> lines = new ArrayList<String>();  // A List can be dynamically resized
while(s.hasNextLine()) lines.add(s.nextLine()); // Store each line in the list
String[] arr = lines.toArray(new String[0]);   // If you really need an Array, use this

score 1 · Accepted Answer · answered May 10 '14 at 08:38

The method you are calling timetable.nextLine.split("\n") will return the Array of String. So every time when you call this method is overwrites your array with new line in file and as the last line is added finally in your array you are getting the lat line at the end. below is the code you can use.

public static void main(String[] args)  throws FileNotFoundException {
       String routeName = "";
       Scanner timetable;
       int count = 0;
       String[] s = new String[10];
       timetable = new Scanner(new File("fileName.txt"));
       while (timetable.hasNextLine()) {
             String line = timetable.nextLine();
             s[count++] = line;
       }
       routeName = s[0];
       System.out.println(routeName);
}

score 0 · Answer 3 · edited May 10 '14 at 08:14

0

Your while loop itterates over all lines and sets the current line to the routeName. Thats why you habe the last line in you string. What you could do is calling a break, when you habe read the first line oft the file. Then you will have the first line.

edited May 10 '14 at 08:14

Marcin Orlowski

72,056
11
123
141

answered May 10 '14 at 08:13

stsc

38
4

String Arrays not returning expected value

3 Answers3