如何从Java中的文件读取随机行

Question

I've made a program that reads a line from a text file. i now need to make it read a random line each time the program is run. This is part of my current code :

if(Score<=5){
word = scan1 .nextLine();
System.out.println(word);
}

Is there any simple way to pick a random line ?

Answer 1

public String getRandomLineFromTheFile(File file)
{
    final RandomAccessFile f = new RandomAccessFile(file, "r");
    final long randomLocation = (long) (Math.random() * f.length());
    f.seek(randomLocation);
    f.readLine();
    return f.readLine();
}

1. This function is biased towards longer lines compared to shorter lines.
2. This function is heavily biased against the first line. (This can be fixed. Think about it.)

Answer 2

I propose that you 1. first obtain the total number of lines in the file. Then 2. obtain a random number within that total. Then 3. skip through the file to the point indicated by the random number. Then 4. read the line of the file.

If you want code I can supply some to get you started, but this should be fairly simple to implement.

Answer 3

as said you can use random to generate a number,
but to read a new line search for it's index for "\\n" new line character
and then seek(RANDOM) to that location and readLine() from that.

Answer 4

generate random number through Random . By that number you can read line from file. You need to put some validation like that line already read or not etc.