ruby set and csv

ruby/EffectiveRuby/set.rb

@@ -0,0 +1,4 @@
+s1 = Set.new(["select", "update"])
+#=> #<Set: {"select", "update"}>
+s1.include?("select")
+#=> true

ruby/EffectiveRuby/weather.rb

@@ -0,0 +1,29 @@
+require 'csv'
+require 'set'
+
+class AnnualWeather
+  attr_reader :readings
+
+  Reading = Struct.new(:date, :high, :low) do
+    def eql?(other)
+      date.eql?(other.date)
+    end
+
+    def hash
+      date.hash
+    end
+  end
+
+  def initialize(filename)
+    @readings = Set.new
+
+    CSV.foreach(filename, headers: true) do |row|
+      @readings << Reading.new(Date.parse(row[0]),
+                                          row[1].to_f,
+                                          row[2].to_f)
+    end
+  end
+end
+
+aw = AnnualWeather.new('weather_data.csv')
+p aw.readings

ruby/EffectiveRuby/weather_data.csv

@@ -0,0 +1,4 @@
+date,high,low
+20160401,25,5
+20160402,27,8
+20160403,30,8