Question

I am trying to reprogram a Java program that I made into Ruby, to help me learn the language. However, I’m having a lot of trouble finding a way to code this particular section of Java code in Ruby:

/* read the data from the input file and store the weights in the 
array list */
Scanner readFile = new Scanner(new FileReader(inFileName));
ArrayList<Weight> listOfWeights = new ArrayList<Weight>();
while (readFile.hasNext()) {
    int pounds = readFile.nextInt();
    int ounces = readFile.nextInt();
    Weight thisWeight = new Weight(pounds, ounces);
    listOfWeights.add(thisWeight);
}

This code takes a file that has a list of integers in two columns (the first being pounds and the second being ounces) like this:

120  2
195 15
200  5
112 11
252  0
140  9

, and makes a bunch of Weight objects using the numbers in each row. Then it adds them to a list. Is there an easy way to do this in Ruby? Here’s what my Ruby program looks like so far:

begin
  puts "Enter the name of the input file > "
  in_file_name = gets
  puts \n

  list_of_weights = []
  File.open(in_file_name, "r") do |infile|
    while (line = infile.gets)

Thanks for the help!

Answer 1

Not equivalent as you asked but since ruby is a dynamic language I think there is no need for such think. So here is how you could do it

  while (line = infile.gets)
    pounds, ounces = line.split(' ')
    p "-#{pounds}- -#{ounces}-"
  end

output

-120- -2-
-195- -15-
-200- -5-
-112- -11-
-252- -0-
-140- -9-

Or a more ruby way (I think)

File.open(in_file_name, "r").each_line do |line|
  pounds, ounces = line.split(' ')
  p "-#{pounds}- -#{ounces}-"
end