string split with regular expression

[Christian Klugesherz]

Hello all,

Could you please help.
There is now 2 hours that I'm trying to fix this issue with regex ...

Text file composed of following

# R22
# Temperature [degree] / Pression relative [bar]
-4	3,33
-2	3,63
0	3,95
2	4,28
4	4,63
6	5

The goal is to save this information in a 2 dimensional array of double
I'm stuck with the regex.
It is not working, and I don't know how to approach the solution

			while ((line = in.readLine()) != null)
			{
				if (!line.startsWith("#") ) {
					String [] tp = line.split("(-?\\d+(,\\d+)?)\t(-?\\d+(,\\d+)?)");

					System.out.println(line);	
					System.out.println ("T="+ tp[0]+ " P=" + tp[1]);
				}
			}

What is wrong ?

Many thanks in advance

Christian

[bob john]

This is used for .delimiter
line.split("(-?\\d+(,\\d+)?)\t(-?\\d+(,\\d+)?)");

If you want to split, you may write only one symbol inside parameters. Try this.
line.split(" ");

[Christian Klugesherz]

Worse :-(

	public void openPressionTemperatureFile() throws IOException {
		String p2tfile = "D:/Users/kluges1/workspace/pac-tool/src/pacp/images/diagrammes enthalpique/P2T_R22.txt";
		BufferedReader in;
		String line;	
		try {
			in = new BufferedReader(new FileReader(p2tfile));
			while ((line = in.readLine()) != null)
			{
				if (!line.startsWith("#") ) {
					String [] tp = line.split(" ");

					System.out.println(line);	
					System.out.println ("T="+ tp[0]+ " P=" + tp[1]);
				}
			}
			in.close();

		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

-20 1,43
java.lang.ArrayIndexOutOfBoundsException: 1
at pacp.test.WinRelP2T.openPressionTemperatureFile(WinRelP2T.java:106)
at pacp.test.WinRelP2T.<init>(WinRelP2T.java:60)
at pacp.test.WinRelP2T$1.run(WinRelP2T.java:46)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)

[Henry Wong]

Christian Klugesherz wrote:Worse :-(

This is because you are not using a space as your delimiter. You are using a tab.

BTW, your first regular expression was pretty complex... including the use of capture groups.  So, obviously, you know your regular expressions. Why not use the regex engine (ie. the java.util.regex.Pattern and java.util.regex.Matcher classes), instead of the split() method of the String class?

Henry

[bob john]

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class NeItema {

	public static void main(String[] args) throws FileNotFoundException {
		
	File file = new File ("tem");
	
	Scanner sken = new Scanner (file);
	
	while (sken.hasNext () ){
	String first = sken.nextLine ();
	String[] second = first.split ("  ");
	
	System.out.println ("second numbers "+ second [1] );
	System.out.println ("first numbers "+second [0]  );
	}
		
		
	}

}

There is very simple and clear example how to split. I used your text file.

[Christian Klugesherz]

Henry Wong wrote:This is because you are not using a space as your delimiter

Sorry, so stupid is my question  :-(
Working well with TAB :-)

[Christian Klugesherz]

Thanks to all :-)

Henry Wong wrote:Why not use the regex engine

Hummm why not :-)

This gives the possibility to separate the 2 values in the line, whatever space or tab for the separation..

	
public void openPressionTemperatureFile() throws IOException {
		String p2tfile = "D:/Users/kluges1/workspace/pac-tool/src/pacp/images/diagrammes enthalpique/P2T_R22.txt";
		BufferedReader in;
		String line;	
		try {
			in = new BufferedReader(new FileReader(p2tfile));
			
			Pattern p = Pattern.compile("(-?\\d+(,\\d+)?)\t(-?\\d+(,\\d+)?)");
			
			while ((line = in.readLine()) != null)
			{
				if (!line.startsWith("#") ) {
					Matcher m = p.matcher(line);
					while (m.find()) {
						System.out.print (m.group());
					}
					System.out.println();
				}
			}
			in.close();

		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

Almost work...
However still something wrong with the regular expression.
The whole line is stored in matcher m.

[Christian Klugesherz]

I got for  now as print result

-20	1,43
-18	1,62
-16	1,83
-14	2,05
-12	2,28
-10	2,52

[Christian Klugesherz]

It works with this code..
But not really understood why

	public void openPressionTemperatureFile() throws IOException {
		String p2tfile = "D:/Users/kluges1/workspace/pac-tool/src/pacp/images/diagrammes enthalpique/P2T_R22.txt";
		BufferedReader in;
		String line;	
		try {
			in = new BufferedReader(new FileReader(p2tfile));
			
			Pattern p = Pattern.compile("(-?\\d+(,\\d+)?)");
			
			while ((line = in.readLine()) != null)
			{
				if (!line.startsWith("#") ) {
					Matcher m = p.matcher(line);
					int i=0;
					while (m.find()) {
						System.out.print ( "   val(" + i + ")=" +  m.group());
						i++;
					}
					System.out.println();
				}
			}
			in.close();

		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

  val(0)=-20   val(1)=1,43
   val(0)=-18   val(1)=1,62
   val(0)=-16   val(1)=1,83
   val(0)=-14   val(1)=2,05
   val(0)=-12   val(1)=2,28
   val(0)=-10   val(1)=2,52
   val(0)=-8   val(1)=2,78
   val(0)=-6   val(1)=3,05
   val(0)=-4   val(1)=3,33
   val(0)=-2   val(1)=3,63

[Junilu Lacar]

Jamie Zawinski, in a Tue 12 Aug 1997 Usenet post wrote: Some people, when confronted with a problem, think “I know, I’ll use regular expressions.” Now they have two problems.

There doesn't seem to be too much variation in your data. I would try to find a simpler way to parse that out. You should never go with code that you don't fully understand, especially when it "seems to work."