1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
|
require 'spec_helper'
require 'csv'
require 'ostruct'
#In weather.dat you’ll find daily weather data for Morristown, NJ for June 2002.
#Download this text file, then write a program to output the day number (column one)
#with the smallest temperature spread (the maximum temperature is the second column, the minimum the third column).
class Day
include Comparable
attr_reader :day, :spread
def initialize(day:, max:, min:)
@day = day
@spread = max - min
end
def <=>(other)
@spread <=> other.spread
end
def self.map_from(row)
Day.new(day: row[0], max: row[1].to_f, min: row[2].to_f)
end
end
class Spread
include Enumerable
def initialize(filename, mapper)
@file_path = File.join(File.dirname(__FILE__), "../fixtures", filename)
@mapper = mapper
end
def each
open_file do |file|
file.each_line.with_index do |line, index|
next if index == 0
next if line.chomp.empty?
yield mapper.map_from(line.split)
end
end
end
private
def open_file
file = File.new(file_path)
yield file
ensure
file.close
end
attr_reader :file_path, :mapper
end
describe "spread" do
subject { Spread.new('weather.dat', Day) }
it 'returns the day with the smallest temperature spread' do
expect(subject.min.day).to eql('14')
end
end
|
