stats

spec_file.rb

require 'rspec'
require_relative 'array_statistics'
 
describe ArrayStats do
 
  it 'Input of an array gives the largest number in the array' do
   expect(ArrayStats.new([1, 2, 3, 4, 2, 5, 3]).largest_num).to eql(5)
  end
 
  it 'Input of an array gives the smallest number in the array' do
    expect(ArrayStats.new([1, 2, 3, 4, 2, 5, 3]).smallest_num).to eql(1)
  end
 
  it 'Input of an array gives the average of the array' do
   expect(ArrayStats.new([1, 2, 3, 4, 2, 5, 3]).average).to eql(2.86)
  end
 
  it 'Input of an array gives the stdev of the array' do
   expect(ArrayStats.new([1, 2, 3, 4, 2, 5, 3]).stdev).to eql(1.25)
  end
 
  it 'Input of an array gives the nth smallest number in the array' do
   expect(ArrayStats.new([1, 2, 3, 4, 2, 5, 3]).nth_smallest(3)).to eql(2)
  end
##################
 
  it 'Input of an array gives the sum of the array' do
   expect(ArrayStats.new([1, 2, 3, 4, 2, 5, 3]).sum).to eql(20)
  end
 
  it 'Input of an array gives the product of the array' do
   expect(ArrayStats.new([1, 2, 3, 4, 2, 5, 3]).product).to eql(720)
  end
 
  it 'Input of an array gives difference between highest and lowest' do
   expect(ArrayStats.new([1, 2, 3, 4, 2, 5, 3]).difference).to eql(4)
  end
 
  it 'Input of an array gives digit frequency' do
   expect(ArrayStats.new([1, 1000, 200, 300, 3000, 4000, 5500]).digit_frequency).to eql({
    1 => 1,
    3 => 2,
    4 => 4
    })
  end
 
end

stats.rb

class ArrayStats
  attr_reader :sum
  def initialize(array)
    @array = array
    average
  end
 
  def largest_num
    @array.sort.last
  end
 
  def smallest_num
    @array.sort.first
  end
 
  def average
    @sum = 0.00
    @array.each do |number|
      @sum += number
    end
    @average = (@sum/@array.length).round(2)
    @sum = @sum.to_i
    @average
  end
 
  def stdev
   distance_squared = 0.00
   @array.each do |number|
    distance_squared += (number - @average)**2
   end
    Math.sqrt(distance_squared/@array.length).round(2)
  end
 
  def nth_smallest(nth)
    @array.sort[nth-1]
  end
 
  def product
    @product = 1
    @array.each do |number|
     @product *= number
   end
   @product
  end
 
  def difference
    @array.sort.last - @array.sort.first
  end
 
  def digit_frequency
    total_array = []
    @array.each do |number|
       total_array  <<  number.to_s.length 
    end
    freq = total_array.inject(Hash.new(0)) { |h,v| h[v] += 1; h }
    p freq
  end
end
 
arraystats = ArrayStats.new([1, 2, 3, 4, 2, 5, 3])
arraystats2 = ArrayStats.new([1, 1000, 200, 300, 3000, 4000, 5500])
 
arraystats2.digit_frequency