Reading the last (or last but 1) line in a text file

[Campbell Ritchie]

Is there an easy way to skip lines in a text file?

I have a text file which reads a bit like this, where %n means newline, and most Britons will recognise AB123456C as a National Insurance number:-

0 1 2 3 4 Campbell Ritchie AB123456C%n
0 12 23 34 45 Campbell Ritchie AB123456C%n
0 123 234 345 456 Campbell Ritchie AB123456C%n
0 1234 2345 3456 4567 Campbell Ritchie AB123456C%n

. . . and I can easily get a java.util.Scanner to read the lines.

But, what I really want is to get it to skip the 1st 2nd and 3rd lines and read the 4th line beginning 0 1234. I have tried all sorts of combinations of while(myScanner.hasNext()){}, while(myScanner.hasNextLine()), myScanner.nextInt(), myScanner.next(), and it happily reads either one line or all five lines (the %n at the end of the 4th line means there is a 5th line with nothing in).

I might use two Scanners, use one to go

 while(scanner1.hasNextLine()
{
   scanner1.nextLine();
   scannerCount++;
}
for (int i = 1; i < scannerCount; i++)
{
   scanner2.nextLine();
} 

. . . but I think there must be a more elegant way to do it.
I don't want to go back to the old J1.4 way of using FileStreams or whatever they were called, because then I have to call Integer.parseInt() for each of the numbers, and scanner2.nextInt() is so much neater.

Any suggestions???

[Jeff Albertson]

I didn't recognize the National Insurance Number, but then again cricket doesn't make sense to me either.
Still, this may be what you're looking for:

import java.io.*;
import java.util.*;
 
public class ScanToEnd {
    public static void main(String[] args) throws IOException {
        Scanner scanner = new Scanner(new File("ScanToEnd.java"));
        String ultimate = null;
        String penultimate = null;
        while (scanner.hasNextLine()) {
            penultimate = ultimate;
            ultimate = scanner.nextLine();
        }
        scanner.close();
        System.out.println("penultimate=" + penultimate);
        System.out.println("ultimate=" + ultimate);
    }
}
//I am the penultimate
//I am the ultimate

[Jody Brown]

A National Insurance Number is the U.K. equivalent of a Social Security Number in the U.S.

[Campbell Ritchie]

Yes, that probably is what I am looking for, Mr Albreachtsen.
It is obvious once you think of it.

Thank you.

[Allion Salvador]

YOU SPELLED HIS NAME WRONG!!!

[Allion Salvador]

Oh, and they are called "FileInputStream" and I think they are fine!

[Jeff Albertson]

Originally posted by Allion Salvador:
YOU SPELLED HIS NAME WRONG!!!

That's OK. It's only my nom de guerre.

[Ricardo Wagemaker]

Jeff Albertson wrote:I didn't recognize the National Insurance Number, but then again cricket doesn't make sense to me either.
Still, this may be what you're looking for:

import java.io.*;
import java.util.*;
 
public class ScanToEnd {
    public static void main(String[] args) throws IOException {
        Scanner scanner = new Scanner(new File("ScanToEnd.java"));
        String ultimate = null;
        String penultimate = null;
        while (scanner.hasNextLine()) {
            penultimate = ultimate;
            ultimate = scanner.nextLine();
        }
        scanner.close();
        System.out.println("penultimate=" + penultimate);
        System.out.println("ultimate=" + ultimate);
    }
}
//I am the penultimate
//I am the ultimate

Hi Jeff,

Old thread but this is exacly what I wanted, except one small detail and I can't figure it out and that is how do I get the 3rd from last line also.

I have before = penultimate and then penultimate = scanner.nextLine(); also but it does not work :-(

Please help if you are still about.

Many Thanks

[Wendy Gibbons]

you need a third variable penulitmatePenultimate

[Campbell Ritchie]

Campbell Ritchie,
Your post was moved to a new topic.

[Campbell Ritchie]

Campbell Ritchie wrote:Campbell Ritchie,
Your post was moved to a new topic.

Talking to yourself again? Sure sign of insanity.