A OO program that reads in a csv of students and grades, and allows a report to be generated for student and classroom grade averages.

assignment_grade.rb

# Grade, contains the name of the assignment and the score
class AssignmentGrade
  attr_accessor :numeric_grade, :assignment
  def initialize(assignment, grade)
    @assignment = assignment
    @numeric_grade = grade.to_f
  end
end

final_grade.rb

# Letter grade
class FinalGrade
  attr_reader :letter
  def initialize(letter)
    @letter = letter
  end
end

grade_reader.rb

# Reads in grade data and instantiates assignment_grades
class GradeReader
  def initialize(file_name)
    @file_name = file_name
  end

  def read_data
    grade_data = []
    CSV.foreach(@file_name, headers: true) do |row|
      grade = row.to_hash.select { |k, v| k != 'name' }
      pupil = []
      grade.each do |k, v|
        pupil << AssignmentGrade.new(k, v)
      end
      grade_data << pupil
    end
    grade_data
  end
end

grade_summary.rb

# Classroom level data and methods
class GradeSummary
  attr_accessor :average, :min_score, :max_score, :standard_deviation
  def initialize(students)
    @students = students
  end

  def total
    @students.map(&:average).reduce(:+)
  end

  def class_average
    @class_average ||= (total / @students.length)
  end

  def min_score
    @min_score = @students.map(&:average).sort.first.round(2)
  end

  def max_score
    @min_score = @students.map(&:average).sort.last.round(2)
  end

  def variance
    @variance ||= @students.map(&:average).inject(0.0) { |sum, average| (sum + (average - class_average)**2) } / (@students.length)
  end

  def standard_deviation
    @standard_deviation = Math.sqrt(variance).round(2)
  end
end

grades.csv

methods.rb

def prompt(question)
  puts "#{question}"
  gets.chomp
end

def grade_assign(students, grade_data)
  students.each_with_index do |student, i|
    student.grades = []
    grade_data[i].each do |grades|
      student.grades << grades
    end
  end
end

def teacher_load(students)
  students.each do |pupil|
    print "#{pupil.name}'s grades:"
    puts "#{pupil.grades.map(&:numeric_grade).join(", ")}"
  end
end

def teacher_report_out(students)
  students.each do |pupil|
    puts "#{pupil.name}'s average: #{pupil.average}"
  end
end

def teacher_letter(students)
  students.each do |pupil|
    puts "#{pupil.name}'s letter grade: #{pupil.final_grade.letter}"
  end
end

def name_switch(students)
  students.each do |pupil|
    pupil.name = pupil.name.split(' ').reverse.join(', ')
  end
end

def student_sort(students)
  students.sort_by(&:name)
end

def teacher_write(students)
  write_file = prompt('What file do you want to write to?')
  File.open(write_file, 'w') do |file|
    students.each do |pupil|
      file.write("#{pupil.name}: Average: #{pupil.average}")
      file.write(" Grade: #{pupil.final_grade.letter}\n")
    end
  end
end

def classroom_report(classroom)
  puts "The class average was: #{classroom.class_average}"
  puts "The lowest average was: #{classroom.min_score}"
  puts "The highest average was: #{classroom.max_score}"
  puts "The standard deviation was: #{classroom.standard_deviation}"
end

program.rb

require_relative 'grade_reader.rb'
require_relative 'student.rb'
require_relative 'assingment_grade.rb'
require_relative 'final_grade.rb'
require_relative 'grade_summary.rb'
require_relative 'student_reader.rb'
require_relative 'methods.rb'
require 'csv'

file_name = prompt('What file do you want to read from?')
grade_data = GradeReader.new(file_name).read_data
students = StudentReader.new(file_name).read_data
grade_assign(students, grade_data)
classroom = GradeSummary.new(students)
teacher_load(students)
teacher_report_out(students)
teacher_letter(students)
classroom_report(classroom)
name_switch(students)
student_sort(students)
teacher_write(students)

student.rb

# Student Class, student requires name, all else optional
class Student
  attr_accessor :name, :average, :final_grade, :grades
  def initialize(name)
    @name = name
  end

  def total
    @grades.map(&:numeric_grade).reduce(:+)
  end

  def average
    @average ||= (total / @grades.length)
  end

  def final_grade
    @final_grade = FinalGrade.new('F') if average < 60
    @final_grade = FinalGrade.new('D') if average >= 60 && average < 70
    @final_grade = FinalGrade.new('C') if average >= 70 && average < 80
    @final_grade = FinalGrade.new('B') if average >= 80 && average < 90
    @final_grade = FinalGrade.new('A') if average >= 90
    @final_grade
  end
end

student_reader.rb

# Reads in data and instantiates students with name
class StudentReader
  def initialize(file_name)
    @file_name = file_name
  end

  def read_data
    students = []
    CSV.foreach(@file_name, headers: true) do |row|
      grad = Student.new(row.to_hash.select { |k, v| k == 'name' }.values.join)
      students << grad
    end
    students
  end
end