Ruby Fundamentals I - Challenge

list_statistics.rb

#  Ruby Fundamentals III - Challenge

# Write a program, given a hardcoded list of test scores, that reports the average score, the lowest score, and the highest score.

SCORES = [75, 100, 85, 65, 84, 87, 95]

def average(numbers)
  numbers = numbers.each {|num| num.to_f}
  sum = numbers.inject(0) {|total, num| total += num}
  number_of_numbers = numbers.length.to_f
  average_of_numbers = sum/number_of_numbers
end

puts "Here are the statistics:"
puts "Average score:  #{sprintf("%.2f",average(SCORES))}"
puts "Lowest score:   #{SCORES.min}"
puts "Highest score:  #{SCORES.max}"

Nice work using a method for calculating the average!

Just a quick note about the each method. Although you're calling the to_f method on each number, it's not actually modifying the numbers array. to_f will return a new object rather than modifying the number in the array but that new object isn't being stored anywhere. Instead you could write something like:

numbers = [75, 100, 85, 65]

floats = []
numbers.each do |num| 
  floats << num.to_f
end

numbers = floats

Now the floats array contains all of the converted values and is then stored back in the numbers variable. Since this is a relatively common use case (converting the values in an array from one type to another) Ruby provides the map method which will return a new array where all of the values have been converted via a code block:

numbers = numbers.map { |num| num.to_f }

This is the equivalent of the above code. The map method is actually defined for the Enumerable module which we'll talk about a bit later in the course: http://ruby-doc.org/core-1.9.3/Enumerable.html#method-i-map