darrencauthon · November 26, 2012 14:06 · Nov 26, 2012 · Nov 26, 2012 · Nov 26, 2012
diff --git a/to_range_spec.rb b/to_range_spec.rb
@@ -69,4 +69,15 @@
       result[2].must_equal 1000..1000
     end
   end
+
+  describe "with dates" do
+    it "should return ranges just like with integers" do
+      result = ['2012-11-26', '2012-11-27', '2012-11-28', '2013-01-01', '2013-01-02', '2013-01-04'].
+        map { |x| Date.parse(x) }.to_range
+      result.count.must_equal 3
+      result[0].must_equal Date.parse('2012-11-26')..Date.parse('2012-11-28')
+      result[1].must_equal Date.parse('2013-01-01')..Date.parse('2013-01-02')
+      result[2].must_equal Date.parse('2013-01-04')..Date.parse('2013-01-04')
+    end
+  end
 end
diff --git a/to_range.rb b/to_range.rb
@@ -1,28 +1,7 @@
-require 'pp'
-require 'date'
-
-
-
-def to_range  low, high, input, output
-  if high > input.length
-    return output.each_slice(2).map {|a| a }.map { |x| x[0]..x[1]}
+class Array
+  def to_range
+    highs = self.select { |x| self.include?(x+1) == false }.sort_by { |x| x }
+    lows = self.select { |x| self.include?(x-1) == false }.sort_by { |x| x }
+    (0...lows.count).map { |i| lows[i]..highs[i] }
   end
-  if low == 0
-    output = Array.new
-    output << input[low]
-  else
-    if input[low]+1 != input[high]
-      output << input[low]  
-      output << input[high] if input[high] 
-    end
-  end
-  to_range  (low+1), (high+1), input, output
 end
-
-
-input = [1,2,3,4,5,100,101,102,400,401,402,403,404,405,406]
-pp to_range  0, 1, input, nil    # => [1..5, 100..102, 400..406]
-
-
-
-
diff --git a/to_range_spec.rb b/to_range_spec.rb
@@ -0,0 +1,72 @@
+require 'minitest/spec'
+require 'minitest/autorun'
+require_relative 'to_range'
+
+describe '#to_range' do
+  describe "empty set" do
+    it "should return an empty set" do
+      [].to_range.count.must_equal 0
+    end
+  end
+
+  describe "one item" do
+    [1, 2, 1001].each do |value|
+      it "should return one range" do
+        result = [value].to_range
+        result.count.must_equal 1
+        result[0].must_equal value..value
+      end
+    end
+  end
+
+  describe "two consecutive items" do
+    [[1,2], [3,4], [10000, 10001]].each do |array|
+      it "should return one range" do
+        result = [array[0],array[1]].to_range
+        result.count.must_equal 1
+        result[0].must_equal array[0]..array[1]
+      end
+    end
+  end
+
+  describe "two nonconsecutive items" do
+    [[1,3], [3, 5], [566, 1001]].each do |array|
+      it "should return two ranges for each item" do
+        result = array.to_range
+        result.count.must_equal 2
+        result[0].must_equal array[0]..array[0]
+        result[1].must_equal array[1]..array[1]
+      end
+    end
+  end
+
+  describe "three consecutive items" do
+    [[1,2,3], [2,3,4], [100,101,102]].each do |array|
+      it "should return one range" do
+        result = array.to_range
+        result.count.must_equal 1
+        result[0].must_equal array.first..array.last
+      end
+    end
+  end
+
+  describe "joe's example" do
+    it "should return one range" do
+      result = [1,2,3,4,5,100,101,102,400,401,402,403,404,405,406].to_range
+      result.count.must_equal 3
+      result[0].must_equal 1..5
+      result[1].must_equal 100..102
+      result[2].must_equal 400..406
+    end
+  end
+
+  describe "unordered example" do
+    it "should return one range" do
+      result = [4,3,100,102,1000,1,2,101].to_range
+      result.count.must_equal 3
+      result[0].must_equal 1..4
+      result[1].must_equal 100..102
+      result[2].must_equal 1000..1000
+    end
+  end
+end
diff --git a/to_range.rb b/to_range.rb
@@ -0,0 +1,28 @@
+require 'pp'
+require 'date'
+
+
+
+def to_range  low, high, input, output
+  if high > input.length
+    return output.each_slice(2).map {|a| a }.map { |x| x[0]..x[1]}
+  end
+  if low == 0
+    output = Array.new
+    output << input[low]
+  else
+    if input[low]+1 != input[high]
+      output << input[low]  
+      output << input[high] if input[high] 
+    end
+  end
+  to_range  (low+1), (high+1), input, output
+end
+
+
+input = [1,2,3,4,5,100,101,102,400,401,402,403,404,405,406]
+pp to_range  0, 1, input, nil    # => [1..5, 100..102, 400..406]
+
+
+
+