Add a file of strings into an arraylist

Question

I'm trying to add this file into an arraylist which I will later compare to another arraylist. So far I have this but it is giving me a compiling error. It is saying that it cannot find the symbol .hasNext and . readLine.

ArrayList<String> america = new ArrayList<String>();
    while((infile2.hasNext()))
    {
        america.add(infile2.nextLine());
    }

Can someone help me figure out how to fix these errors?

At a guess you're infile2 is probably something like a BufferedReader when it should be a Scanner — Reimeus
– Reimeus, Commented Apr 16, 2014 at 2:37
Yes it is a bufferedReader but my teacher says not to change it. So I can't make it into a scanner — Ayoshna
– Ayoshna, Commented Apr 16, 2014 at 2:38

Reimeus · Accepted Answer · 2014-04-16 03:07:32Z

1

Yes it is a bufferedReader

BufferedReader doesnt have a hasNext method, therefore you can use readLine

String line;
while((line = infile2.readLine()) != null) {
    americaList.add(line);
}
...

Or if you could use Files

List<String> americaList = 
         Files.readAllLines(Paths.get("list.txt"), StandardCharsets.UTF_8);

edited Apr 16, 2014 at 3:07

answered Apr 16, 2014 at 2:40

Reimeus

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Comments

merlin2011 · Accepted Answer · 2014-04-16 02:42:13Z

1

Here is one possible way to do it.

import java.util.Scanner;

Scanner inFile2 = new Scanner(new File("INPUT_FILE_NAME"));

Then, change your loop to use hasNextLine() instead of hasNext(). For Java's Scanner you should always pair the has with the corresponding type of next.

You can wrap the BufferedReader that someone hands you inside a Scanner.

 Scanner inFile = new Scanner(myBufferedReader);

edited Apr 16, 2014 at 2:42

answered Apr 16, 2014 at 2:35

merlin2011

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4 Comments

Ayoshna Over a year ago

I'm not allowed to change the BufferedReader file into a scanner.... Is there another way?

merlin2011 Over a year ago

@Ayoshna, See the update and let me know whether you are allowed to wrap it.

Ayoshna Over a year ago

Nope. He has given us this line and we are not allowed to change his work. This is what it says: BufferedReader infile2 = new BufferedReader( new FileReader("allPresidents.txt") );

merlin2011 Over a year ago

@Ayoshna, Can you add a line below it, that says Scanner infile3 = new Scanner(infile2);? That does not change his original line.

zg_spring · Accepted Answer · 2014-04-16 02:41:24Z

0

       /**
 * one time read all
 * 
 * @param location
 * @return
 */
public static List<String> readLine(String location){
    BufferedReader is = null;
    List<String> result = new ArrayList<String>();
    try {
        is = new BufferedReader(new FileReader(new File(location))); 
        String line = null;
        while((line = is.readLine())!=null){
            result.add(line);
        }
    } catch (FileNotFoundException e) {
        throw Exceptions.unchecked(e);
    } catch (IOException e) {
        throw Exceptions.unchecked(e);
    } finally{
        if (is != null) {
            try {
                is.close();
            } catch (IOException e) {
                throw Exceptions.unchecked(e);
            }
        }
    }

    return result;
}

answered Apr 16, 2014 at 2:41

zg_spring

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3 Comments

zg_spring Over a year ago

A simple text scanner which can parse primitive types and strings using regular expressions. I think BufferedReader will be better.

Ayoshna Over a year ago

Can you explain the line where you assigned is. What do you mean by location?

zg_spring Over a year ago

location is the file's path, example c:\\a.txt

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