Scan a text file.

[john larry]

What would i do to scan a text file for a certain line of text, and notate down how many times it has it. like would probably do something like:

If()
{   
Text1++;
}

I'm not sure where to go from there though.

[ November 30, 2008: Message edited by: john larry ]
[ November 30, 2008: Message edited by: john larry ]

[Jeanne Boyarsky]

John,
If you are on Java 5 (and this isn't a school project), you can use the Scanner class. If not, you'll have to read the lines of the file yourself. Either way, you need to figure out how to express what you want to match in Java.

If you share which approach you plan to take (scanner vs read file), you may get some more concrete advice.

[Campbell Ritchie]

Go through the regular expressions tutorial; you can probably find whether the pattern you are looking for is matched in the file, then whenever it is you can increment your counter.

You might do well to look at the "quantifiers" section; depending on what you are looking for, you might get a different count with a greedy quantifier from a reluctant quantifier.

Other people will doubtless have other ideas about this question.

[john larry]

This is for school, but it is using the Scanner class. Here is all that i have so far:

import java.util.Scanner;
import java.io.File;
import java.io.IOException;
public class ScanText
{
   public static void main(String[] args) throws IOException
   {
      
      int text1 = 0;
      int text2 = 0;
      int text3 = 0;
      int text4 = 0;
      File fileName = new File("test1.txt");
      Scanner inFile = new Scanner(fileName);
      
      System.out.println("Number of Text One: " + text1);
      System.out.println("Number of Text Two: " + text2);
      System.out.println("Number of Text Three: " + text3);
      System.out.println("Number of Text Four: " + text4);
      
      inFile.close();
    }
}

But, as you can see i can't think of how to scan the text file "test1.txt" for the three different words and mark down how many times they occur.

[jaywee]

I suppose you've known the line you want to check in the file.so here is my code:

  import java.util.*;
public class TestScanFile{
   public static void main(String[] args)throws Exception{
  java.io.File file = new java.io.File("yourFile");
  Scanner input = new Scanner(file);
  int count = 0;
  while(input.hasNext()){
 if(input.nextLine().equals("yourString"))
count ++;
}
  if(count > 0) System.out.println( count);
  if(count == 0) System.out.println("String no found!");
   }
}  

wish can help you!

[john larry]

My code:

import java.util.Scanner;
import java.io.File;
import java.io.IOException;
public class Family
{
   public static void main(String[] args) throws IOException
   {
      
      int GBBG = 0;
      int BB = 0;
      int GG = 0;
      int number = GBBG + BB + GG;
      java.io.File file = new java.io.File("test1.txt");
      Scanner inFile = new Scanner(file);
      while(inFile.hasNext())
      {
         if(inFile.nextLine().equals("GB"))
            GBBG ++;
         if(inFile.nextLine().equals("BG"))
            GBBG ++;
         if(inFile.nextLine().equals("BB"))
            BB ++;
         if(inFile.nextLine().equals("GG"))
            GG ++;
      }
      
      System.out.println("Sample Size: " + number);
      System.out.println("Two Boys: " + BB);
      System.out.println("One Boy, One Girl: " + GBBG);
      System.out.println("Two Girls: " + GG);
      
      inFile.close();
    }
}

I'm getting this error when i run it, it compiles fine:

java.util.NoSuchElementException: No line found
at java.util.Scanner.nextLine(Scanner.java:1471)
at Family.main(Family.java:19)
java.util.NoSuchElementException: No line found
at java.util.Scanner.nextLine(Scanner.java:1471)
at Family.main(Family.java:19)
java.util.NoSuchElementException: No line found
at java.util.Scanner.nextLine(Scanner.java:1471)
at Family.main(Family.java:19)

[Jesper de Jong]

jaywee, please check your private messages for an administrative matter. You can see them by clicking My Private Messages.

[Campbell Ritchie]

You can get NosuchElementExceptions if the Scanner tries to read more lines than there are in the text file. Remember there are Scanner methods for reading all sorts of different data types directly from text.