Java - Using Delimiter not removing special character

Question

The text file contains the following data. I wish to remove the '$' from each row of the text file. I also wish to store the Name,Drink and Cost in variables for future manipulation. However, that can be performed later. I do not understand what is wrong with my code, Here is the Textfile Data:

Problem solved using Regex escape pattern. I had to replace the "$" with "\s*\$\s*"

Rubin$Vodka$55
Alex$Gin$22
Max$Water$FREE

Code:

  File filename = new File("animals2.txt");        
        try{
        Scanner sc = new Scanner(filename);
        String line = sc.nextLine();
        Scanner linesc = new Scanner(line).useDelimiter("$");

        while(linesc.hasNext()){
            String name = linesc.next();
            txaDisplay.append(name + "\n");

        }
    }
    catch(Exception e){
                    e.printStackTrace();
    }

Possible duplicate of [How do I use a delimiter in Java Scanner?](http://stackoverflow.com/questions/28766377/how-do-i-use-a-delimiter-in-java-scanner) — AxelH, Oct 17 '16 at 10:59
You had your answer but the idea is to read how useDelimeter work. This is well explain in the duplicated question. The parameter is a regex, `$` is a special character. — AxelH, Oct 17 '16 at 11:22

score 4 · Accepted Answer · answered Oct 17 '16 at 11:07

4

Simply change this line of code:

 Scanner linesc = new Scanner(line).useDelimiter("\\s*\\$\\s*");

You need to pass a regular expression pattern escaping the $ sign.

answered Oct 17 '16 at 11:07

Daniele

1,332
1
13
24

Thank you, problem solved with regex escape pattern! – Ryan Teller Oct 17 '16 at 11:13
Slight problem, it only prints the first line – Ryan Teller Oct 17 '16 at 11:18
Because you only loop on the first line of the first Scanner you used... – AxelH Oct 17 '16 at 11:52

Vikas Jaiswal · Answer 2 · 2016-10-17T13:16:49.287

You can try this..

File filename = new File("animals2.txt");        
    try{
    Scanner sc = new Scanner(filename);

    while(sc.hasNext())
    {
        StringBuffer txaDisplay = new StringBuffer();
         String line = sc.nextLine();
         StringTokenizer linesc = new StringTokenizer(line,"/($)/g");

         while(linesc.hasMoreElements()){
            String name = linesc.nextToken();
            txaDisplay.append(name+" ");
         }
         System.out.println(txaDisplay);
    }
  }
  catch(Exception e){
    e.printStackTrace();
  }

uoyilmaz · Answer 3 · 2016-10-17T11:14:23.643

0

Use the split method of the String. You cannot accomplish what you are trying with Scanner.

public static void main( String[] args)
{
    File filename = new File( "animals2.txt");

    try{
        Scanner sc = new Scanner( filename);

        while( sc.hasNextLine())
        {
            String line = sc.nextLine();
            String[] arr = line.split( "\\$");

            for( String str : arr)
            {
                txaDisplay.append( str + "\n");
            }
        }
    } catch( Exception e) {
        e.printStackTrace();
    }
}

As a side note, do not use StringTokenizer. Here is what the documentation says:

StringTokenizer is a legacy class that is retained for compatibility reasons although its use is discouraged in new code. It is recommended that anyone seeking this functionality use the split method of String or the java.util.regex package instead.

edited Oct 17 '16 at 11:14

answered Oct 17 '16 at 11:03

uoyilmaz

3,035
14
25

This will not work if you have a line like this : "$$" if you need to keep the same number of lines per original lines. – AxelH Oct 17 '16 at 11:07
Nothing in the original post indicates that $$ is a valid input line. – uoyilmaz Oct 17 '16 at 11:09
Clarification of my above comment, it does not remove the $ sign – Ryan Teller Oct 17 '16 at 11:11
Well, nothing tell you it is an invalid input line – AxelH Oct 17 '16 at 11:13
@AxelH well, the sample input does. – uoyilmaz Oct 17 '16 at 11:16
I give you that since this will work better with this regex ;) – AxelH Oct 17 '16 at 11:20
It works but it only prints a single line (well a single line from the textile, i.e Rubin/nVodka/n55 – Ryan Teller Oct 17 '16 at 11:21
It might be related to how txaDisplay.append works, it works as intended when I use System.out.print( str + "\n"); – uoyilmaz Oct 17 '16 at 11:22
Okay fixed it, how can i store each type in a variable for manipulation. (name/drink/price etc)? – Ryan Teller Oct 17 '16 at 14:04
I just removed the for loop and created variables storing the drink at[0] name at[1] and price at [3] – Ryan Teller Oct 17 '16 at 15:09

score 0 · Answer 4 · answered Oct 17 '16 at 11:19

Try this

        try {
        File file = new File("animals2.txt");
        List<String> lines = Files.readAllLines(file.toPath(), StandardCharsets.UTF_8);
        for(String s: lines)
        {
            String str[] = s.split("$");
            for(int i = 0; i < str.length; i++)
            {
                 txaDisplay.append(str[i] + "\n");
            }
        }
    } catch (IOException e) {
        e.printStackTrace();
    }

score 0 · Answer 5 · answered Oct 17 '16 at 11:47

If you can, use Guava's Splitter.

File filename = new File("animals2.txt");
final Splitter dollarSplitter = Splitter.on('$'); // checks for the char, not the regex.
try (Scanner sc = new Scanner(filename)) {
  String line = sc.nextLine();
  for (String name: dollarSplitter.split(line)) {
    txaDisplay.append(name + "\n");
  }
} catch(Exception e) {
  e.printStackTrace();
}

AxelH · Answer 6 · 2016-10-17T12:05:15.690

Here is how you need to do to loop correctly on each line using the delimiter correctly: (based on your code)

Scanner sc = null, scLine = null;
    try{
        sc = new Scanner(new File("./test.txt")); //CHANGE THE FILE HERE

        String s;
        while(sc.hasNext()){
            scLine = new Scanner(sc.nextLine());
            scLine.useDelimiter("\\$");
            while(scLine.hasNext()){
                s = scLine.next();
                System.out.println(">" + s); //HERE YOU NEED TO APPEND INTO YOUR INSTANCE
            }
            System.out.println("#"); //AND REMOVE THIS LINE. I WORKED IN CONSOLE TO TEST THIS
            scLine.close();
        }
        sc.close();
    } catch (Exception e){
        e.printStackTrace();
    } finally {
        if(scLine != null) scLine.close();
        if(sc != null) sc.close();
    }

The first loop is design to read EVERY line of the file. For each line, you use a Scanner that will use the regex to split the line based on the $ sign.

This could be done with the String.split("") methods but I kept your design here. (Split use a regex but remove empty cell on the beginning and on the end).

And of course, you need to close every scanner correctly. So during the loops and in the finally in case of an exception.

score -2 · Answer 7 · answered Oct 17 '16 at 10:59

-2

String[] parts = line.split("$");
String name = parts[0];
String alcohol = parts[1];
String price = parts[2];

answered Oct 17 '16 at 10:59

Alex Klimashevsky

2,457
3
26
58

@AxelH of cause. you need to think about corner cases yourself – Alex Klimashevsky Oct 17 '16 at 11:08
Well, nothing warns him that the split methods trim the empty cells (except the doc)... so he might be stuck a long time before he understand that. And since you did not explain anything... well this is not a good answer. – AxelH Oct 17 '16 at 11:12

Java - Using Delimiter not removing special character

7 Answers7