ruby - series

ruby/series/README.md

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+# Series
+
+Given a string of digits, output all the contiguous substrings of length `n` in
+that string.
+
+For example, the string "49142" has the following 3-digit series:
+
+- 491
+- 914
+- 142
+
+And the following 4-digit series:
+
+- 4914
+- 9142
+
+And if you ask for a 6-digit series from a 5-digit string, you deserve
+whatever you get.
+
+Note that these series are only required to occupy *adjacent positions*
+in the input; the digits need not be *numerically consecutive*.
+
+* * * *
+
+For installation and learning resources, refer to the
+[exercism help page](http://exercism.io/languages/ruby).
+
+For running the tests provided, you will need the Minitest gem. Open a
+terminal window and run the following command to install minitest:
+
+    gem install minitest
+
+If you would like color output, you can `require 'minitest/pride'` in
+the test file, or note the alternative instruction, below, for running
+the test file.
+
+Run the tests from the exercise directory using the following command:
+
+    ruby series_test.rb
+
+To include color from the command line:
+
+    ruby -r minitest/pride series_test.rb
+
+
+## Source
+
+A subset of the Problem 8 at Project Euler [http://projecteuler.net/problem=8](http://projecteuler.net/problem=8)
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.

ruby/series/series.rb

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+class Series
+  def initialize(digits)
+    @digits = digits
+  end
+
+  def slices(slice_length)
+    if slice_length > @digits.length
+      raise ArgumentError
+    end
+
+    slices = []
+    0.upto(@digits.length - slice_length) do |i|
+      slices.push @digits.slice(i, slice_length)
+    end
+    slices
+  end
+end

ruby/series/series_test.rb

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+require 'minitest/autorun'
+require_relative 'series'
+
+class SeriesTest < Minitest::Test
+  def test_simple_slices_of_one
+    series = Series.new('01234')
+    assert_equal ['0', '1', '2', '3', '4'], series.slices(1)
+  end
+
+  def test_simple_slices_of_one_again
+    # skip
+    series = Series.new('92834')
+    assert_equal ['9', '2', '8', '3', '4'], series.slices(1)
+  end
+
+  def test_simple_slices_of_two
+    # skip
+    series = Series.new('01234')
+    assert_equal ['01', '12', '23', '34'], series.slices(2)
+  end
+
+  def test_other_slices_of_two
+    # skip
+    series = Series.new('98273463')
+    expected = ['98', '82', '27', '73', '34', '46', '63']
+    assert_equal expected, series.slices(2)
+  end
+
+  def test_simple_slices_of_two_again
+    # skip
+    series = Series.new('37103')
+    assert_equal ['37', '71', '10', '03'], series.slices(2)
+  end
+
+  def test_simple_slices_of_three
+    # skip
+    series = Series.new('01234')
+    assert_equal ['012', '123', '234'], series.slices(3)
+  end
+
+  def test_simple_slices_of_three_again
+    # skip
+    series = Series.new('31001')
+    assert_equal ['310', '100', '001'], series.slices(3)
+  end
+
+  def test_other_slices_of_three
+    # skip
+    series = Series.new('982347')
+    expected = ['982', '823', '234', '347']
+    assert_equal expected, series.slices(3)
+  end
+
+  def test_simple_slices_of_four
+    # skip
+    series = Series.new('01234')
+    assert_equal ['0123', '1234'], series.slices(4)
+  end
+
+  def test_simple_slices_of_four_again
+    # skip
+    series = Series.new('91274')
+    assert_equal ['9127', '1274'], series.slices(4)
+  end
+
+  def test_simple_slices_of_five
+    # skip
+    series = Series.new('01234')
+    assert_equal ['01234'], series.slices(5)
+  end
+
+  def test_simple_slices_of_five_again
+    # skip
+    series = Series.new('81228')
+    assert_equal ['81228'], series.slices(5)
+  end
+
+  def test_simple_slice_that_blows_up
+    # skip
+    series = Series.new('01234')
+    assert_raises ArgumentError do
+      series.slices(6)
+    end
+  end
+
+  def test_more_complicated_slice_that_blows_up
+    # skip
+    slice_string = '01032987583'
+
+    series = Series.new(slice_string)
+    assert_raises ArgumentError do
+      series.slices(slice_string.length + 1)
+    end
+  end
+
+  def test_sequential_slices
+    # skip
+    series = Series.new('1234')
+    assert_equal ['12', '23', '34'], series.slices(2)
+    assert_equal ['123', '234'], series.slices(3)
+  end
+end