I want to read data from a line in a file. in Java

Question

I'm currently trying to read certain data from multiple lines(from a specified file) in java.

For example with the lines below i want to store the numerical values from each line in an array, i don't want to read the entire line into an array(i can do that already)

      Firstname 100700 Lastname
      Firstname 260000 Lastname
      Firstname 303000 Lastname
      Firstname 505050 Lastname

How would i go about putting something in my code which allows the program to read the numerical data in my scenario.(Btw the spaces are supposed to be there) BufferedReader input;

    input = new BufferedReader(new FileReader("file.txt"));// file to be read from
    String Line;
    int i = 0;
    int[]number=new int[4];
    while (Line != null)
    {
        Line = input.readLine(); 

       // Then i would need something down here to read the numerical values?
        number[i]=????

        i++
    }

Any help would be appreciated.

Thanks.

Answer 1

Hava a look on String.split() and Integer.parseInt() .

You can use Line.split(" ") to split your String into a String[] and then use Integer.parseInt(myArray[1]) to get the number as an int .

Also note: in java, the convention is that variables start with lower case letter, so you should consider renaming Line -> line

Answer 2

input = new BufferedReader(new FileReader("file.txt"));// file to be read from
String line;
int i = 0;
int[]number=new int[4];
while (line != null)
{
    line = input.readLine(); 
    // here is my refinement
    String[] x = line.Split();
    System.out.println("FirstName: " + x[0]);
    System.out.println("Number: " + x[1]);
    System.out.println("LastName: " + x[2]);

    i++
}

Answer 3

Try this

String line = input.readLine();
if (line != null) {
   int number = Integer.parseInt(line.replaceAll("[^\\d]", ""));
   ...
}

Answer 4

Scanner has .hasNextInt() and .nextInt() . You can use those to read the numbers. Otherwise you could just use some regexes with the Pattern class, or use amit's suggestion.