Parsing CSV file

Suppose you have your input as a string in a variable, say row,

#Filename: test.rb

row = "4217,23,4217:0.1304,11045842:0.0870,11027563:0.0435,15055960:0.0435,12556773:0.0435,10317812:0.0435,21268053:0.0435,14982717:0.0435,12560416:0.0435,21684075:0.0435,12177392:0.0435,878710:0.0435,21777845:0.0435,11045966:0.0435,17109375:0.0435,15701596:0.0435,10312162:0.0435,11045878:0.0435";

row=row.split(',').map do |x|
        if(x.index(':')!=nil)
            x[0..(x.index(':')-1)]
        else
            x
        end
    end

keyElement = row[0];
arrayElement = row[2..-1];

puts keyElement;
for i in 0..arrayElement.length-1
    print(arrayElement[i] + ", ");
end
puts arrayElement[-1];

Here keyElement would contain 'A' and arrayElement would contain the comma seperated values as an array.

For your sample data, it gives:

>>ruby test.rb
4217
4217, 11045842, 11027563, 15055960, 12556773, 10317812, 21268053, 14982717, 12560416, 21684075, 12177392, 878710, 21777845, 11045966, 17109375, 15701596, 10312162, 11045878, 11045878

I would however recommend a hash, assuming you need to associate the array with the value 'A':

#row is mapped as before

hashElement = Hash.new();
hashElement[row[0]] = row[2..-1];