Random Line reading in text file
I am trying to read a random line in a text file but every time i read it it reads first line of the file any one can help me what is the problem in the code is or provide me with a new code.
BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
File file = new File("word.txt");
if(!file.exists())
{
System.out.println("File does not exist.");
System.exit(0);
}
try{
//Open the file for reading
RandomAccessFile raf = new RandomAccessFile(file, "r");
raf.seek(file.length());//Seek to end of file
System.out.println("Read full line: " + raf.readLine());
//str2 is a String
str2 = str2 + raf.readLine();
System.out.println(""+str2);
raf.close();
System.out.println("Successfully");
}
catch(IOException ioe)
{
System.out.println(ioe.getMessage());
}
my text file look like in this format
mind
hate
Abhor
Bigot
narrow
prejudiced
person
Counterfeit
fake
false
give
voting
rights
Hamper
hinder
obstruct
Kindle
to
start
fire
harmful
poisonous
lethal
Hi, RandomAccessFille is not used to read one random line in yourfile. for that, you have to count lines in your file and pick a random number between 1 and the number of line (see Random)to select a line.Hope that help,Jack
Next time when posting code, please use code tags: http://forum.java.sun.com/help.jspa?sec=formatting
A RandomAccessFile has nothing to do with getting a (pseudo) random line number from a file.
You should also split things up in separate methods:
- a method for counting the number of lines in a file;
- a method to get the N-th line from a file.
In your main method, you call the method which counts the number of lines N in a file and then generate a (pseudo) random number between 1 and N. Use the java.util.Random class for this.
When you have generated that number, call the other method to get that specific line number.
Here's a small start:
import java.io.*;
import java.util.*;
public class Main {
public static String getLineNumber(int number) throws FileNotFoundException {
// your code here
}
public static int countLines(String fileName) throws FileNotFoundException {
// your code here
}
public static void main(String[] args) throws Exception {
int numberLines = countLines("word.txt");
Random generator = new Random();
int randomNumber = generator.nextInt(numberLines)+1;
String randomLine = getLineNumber(randomNumber);
System.out.println("Line "+randomNumber+" = '"+randomLine+"'");
}
}
In both methods, you can use the java.util.Scanner class to read lines from the file.
Have a look at the API docs of the Scanner class:
http://java.sun.com/j2se/1.5.0/docs/api/java/util/Scanner.html (including code samples!)
Good luck.
all i have to do is to read a random line from the text line and store it in array
can you please provide the code for
public static String getLineNumber(int number) throws FileNotFoundException {
// your code here
}
public static int countLines(String fileName) throws FileNotFoundException {
// your code here
}
You're welcome for the previous answer!> all i have to do is to read a random line from the> text line and store it in array> can you please provide the code for>...It's your homework, not mine. You do it yourself.
i am little busy in my work i also have to do other projects. it is the part of the project which in not working well. If you kindly help me in making the code i shall be very thanks full. I am making Hangman game only this part was troubling me a lot. i have done every thing except this.
> i am little busy in my work i also have to do other
> projects. it is the part of the project which in not
> working well. If you kindly help me in making the
> code i shall be very thanks full.
Sorry but your being 'busy' is not our problem. Since this is obviously homework it would not be ethical for us to give you the code. You have already be told that using RandomAccessFile is not the way to go yet you keep expecting to use it.
Read the lines of the file when your program starts and store the lines in an ArrayList. It is then very easy to get a random line using java.util.Random.
>i am little busy in my work i also have to do other projects. it is the part of the
>project which in not working well. If you kindly help me in making the code i
>shall be very thanks full. I am making Hangman game only this part was
>troubling me a lot. i have done every thing except this.
Ofcourse nobdy else has anything to do but to serve slackers..
Anyhow the code is really easy to fix. You only need to learn what the metod readLine does.
I.e. readLine(); reads the first line of an file, it also moves the row counter up by 1. That means the next time you call for readLine(); you will read the next line in the textfile.
Examplecode
BufferedReader br = new BufferedReader(new FileReader("File with path.txt"));
String txtLine = "";
txtLine = br.readLine(); //Gives first line in the txt file
txtLine = br.readLine(); //Gives second line in the txt file
txtLine = br.readLine(); //Gives third line in the txt file
and so on.
Here is even the random maker:
int random = (int) ((int) 1000 * Math.random()); //will give an number between 0 and 1000. or is it from 0 - 1000? hmmm... aint that important atm..
That is all you need to understand... Now "just" make it read an random row.
I will give you an hint. Use an for loop.
is RandomAccessFile class slower than the normal FileInputStream or FileOutputStream when using read(byte[]) or write(byte[]) methods? or they have the same speed?
