Java,Read file content to arraylist

Question

I am reading a file content to ArrayList so I can later manipulate the data. But when I try to print to console the content is repeatedly displayed. I online want to be able to print the five lines. How can i adjust the code so that when i display on the console it can only display the five lines with repeatedly displaying the results? In the file I have

After reading to list and display to console the result is

I only want to display the five lines.

Code:

public void testread(){
    System.out.println("Enter filename:\n");
    String filename=Keyboard.readInput();
    File myfile=new File(filename);
    try (BufferedReader scanfile=new BufferedReader(new FileReader(myfile))) {
        String str;
        List<String>list=new ArrayList<String>();

        while ((str=scanfile.readLine())!=null) {
            int i;
            list.add(str);

            for (i=0; i<list.size(); i++) {
                System.out.println(list.get(i));
            }
        }
    } catch (IOException e) {
        System.out.println("Error reading from file " + e.getMessage());
    }
}

Possible duplicate of Java reading a file into an ArrayList? — Samuel Philipp
– Samuel Philipp, Commented Apr 23, 2019 at 18:24

Bigbob556677 · Accepted Answer · 2019-04-23 23:51:26Z

1

You need to move your print for loop out of your while loop. Each iteration of your while loop is then printing every value in the list. Like so:

public void testread(){

    System.out.println("Enter filename:\n");
    String filename=Keyboard.readInput();
    File myfile=new File(filename);
    try(BufferedReader scanfile=new BufferedReader(new FileReader(myfile))){
        String str;
        List<String>
        list=new ArrayList<String>();
        while((str=scanfile.readLine())!=null)
        {
            int i;
            list.add(str);
        }
        // then print the list
        for(i=0;i<list.size();i++) {
            System.out.println(list.get(i));
        }
    }catch (IOException e){
        // Print error in case of failure.
        System.out.println("Error reading from file " + e.getMessage());
    }
}

edited Apr 23, 2019 at 23:51

Bigbob556677

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answered Apr 23, 2019 at 18:29

Illusion

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Comments

Samuel Philipp · Accepted Answer · 2019-04-23 18:28:53Z

0

Just move the for loop outside the while loop.

public void testread(){
    System.out.println("Enter filename:\n");
    String filename=Keyboard.readInput();
    File myfile=new File(filename);
    try (BufferedReader scanfile=new BufferedReader(new FileReader(myfile))) {
        String str;
        List<String>list=new ArrayList<String>();

        while ((str=scanfile.readLine())!=null) {
            int i;
            list.add(str);
        }

        for(i=0;i<list.size();i++) {
            System.out.println(list.get(i));
        }
    } catch (IOException e) {
        System.out.println("Error reading from file " + e.getMessage());
    }
}

edited Apr 23, 2019 at 18:28

Samuel Philipp

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answered Apr 23, 2019 at 18:26

eeijlar

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