Discussion on: Daily Challenge #216 - Rainfall

[windeep]

Ruby solution

def mean(town, strng)
   return -1 if (numbers=extract_data(town, strng)).nil?
   numbers.sum/12
end

def variance(town, strng)
  return -1 if (numbers=extract_data(town, strng)).nil?
  mean = numbers.sum/12
  variance =numbers.map {|x| (x-mean)**2} .sum/12
end

def extract_data(town,strng)
  data_hash = strng.split("\n").map{ |str| str.split(":") }.to_h
  return nil if data_hash[town].nil?
  numbers = data_hash[town].scan(/\d+.\d+/).map(&:to_f)
end