arrays exercises: completed

ruby_basics/6_arrays/exercises/array_exercises.rb

@@ -1,24 +1,30 @@
 def nil_array(number)
+  Array.new(number)
   # return an array containing `nil` the given number of times
 end
 
 def first_element(array)
+  array.first
   # return the first element of the array
 end
 
 def third_element(array)
+  array[2]
   # return the third element of the array
 end
 
 def last_three_elements(array)
+  array.last(3)
   # return the last 3 elements of the array
 end
 
 def add_element(array)
+  array.push(20)
   # add an element (of any value) to the array
 end
 
 def remove_last_element(array)
+  x = array.pop
   # Step 1: remove the last element from the array
 
   # Step 2: return the array (because Step 1 returns the value of the element removed)
@@ -27,35 +33,44 @@ def remove_last_element(array)
 
 def remove_first_three_elements(array)
   # Step 1: remove the first three elements
-
+  array.shift
+  array.shift
+  array.shift
   # Step 2: return the array (because Step 1 returns the values of the elements removed)
   array
 end
 
 def array_concatenation(original, additional)
+  original.concat(additional)
   # return an array adding the original and additional array together
 end
 
 def array_difference(original, comparison)
+  original - comparison
   # return an array of elements from the original array that are not in the comparison array
 end
 
 def empty_array?(array)
+  array.empty?
   # return true if the array is empty
 end
 
 def reverse(array)
+  array.reverse
   # return the reverse of the array
 end
 
 def array_length(array)
+  array.length
   # return the length of the array
 end
 
 def include?(array, value)
+  array.include?(value)
   # return true if the array includes the value
 end
 
 def join(array, separator)
+  array.join(separator)
   # return the result of joining the array with the separator
 end

ruby_basics/6_arrays/spec/array_exercises_spec.rb

@@ -9,152 +9,152 @@
     end
 
     # remove the 'x' from the line below to unskip the test
-    xit 'returns an array containing 2 nil values' do
+    it 'returns an array containing 2 nil values' do
       expect(nil_array(2)).to eq([nil, nil])
     end
   end
 
   describe 'first element exercise' do
 
-    xit 'returns the first element of an array of numbers' do
+    it 'returns the first element of an array of numbers' do
       expect(first_element([2, 4, 6, 8, 10])).to eq(2)
     end
 
-    xit 'returns the first element of an array of strings' do
+    it 'returns the first element of an array of strings' do
       expect(first_element(['foo', 'bar'])).to eq('foo')
     end
   end
 
   describe 'third element exercise' do
 
-    xit 'returns the third element of an array of numbers' do
+    it 'returns the third element of an array of numbers' do
       expect(third_element([2, 4, 6, 8, 10])).to eq(6)
     end
 
-    xit 'returns nil if the array does not have a third element' do
+    it 'returns nil if the array does not have a third element' do
       expect(third_element(['foo', 'bar'])).to eq(nil)
     end
   end
 
   describe 'last three elements exercise' do
 
-    xit 'returns an array of the last three elements' do
+    it 'returns an array of the last three elements' do
       expect(last_three_elements([2, 4, 6, 8, 10])).to eq([6, 8, 10])
-    end
+      end
 
-    xit 'returns all of the elements when there are less than 3 elements' do
+    it 'returns all of the elements when there are less than 3 elements' do
       expect(last_three_elements(['foo', 'bar'])).to eq(['foo', 'bar'])
     end
   end
 
   describe 'add element exercise' do
 
-    xit 'increases the length of an array by 1' do
+    it 'increases the length of an array by 1' do
       numbers = [1, 2, 3, 4]
       expect { add_element(numbers) }.to change { numbers.length }.by(1)
     end
 
-    xit 'increases the length of an empty array by 1' do
+    it 'increases the length of an empty array by 1' do
       data = []
       expect { add_element(data) }.to change { data.length }.by(1)
     end
   end
 
   describe 'remove last element exercise' do
 
-    xit 'returns the array without the last element' do
+    it 'returns the array without the last element' do
       expect(remove_last_element([1, 3, 5])).to eq([1, 3])
     end
 
-    xit 'returns an empty array when the array only has one element' do
+    it 'returns an empty array when the array only has one element' do
       expect(remove_last_element(['foo'])).to eq([])
     end
   end
 
   describe 'remove first three elements exercise' do
 
-    xit 'returns the array without the first three elements' do
+    it 'returns the array without the first three elements' do
       expect(remove_first_three_elements([1, 3, 5, 7, 9])).to eq([7, 9])
     end
 
-    xit 'returns an empty array when the array has less than 3 elements' do
+    it 'returns an empty array when the array has less than 3 elements' do
       expect(remove_first_three_elements(['foo', 'bar'])).to eq([])
     end
   end
 
   describe 'array concatenation exercise' do
 
-    xit 'returns an array adding two arrays of numbers together' do
+    it 'returns an array adding two arrays of numbers together' do
       expect(array_concatenation([1, 3, 5], [2, 4, 6])).to eq([1, 3, 5, 2, 4, 6])
     end
 
-    xit 'returns an array adding arrays of strings and numbers together' do
+    it 'returns an array adding arrays of strings and numbers together' do
       expect(array_concatenation(['a', 'b', 'c'], [1, 2, 3])).to eq(['a', 'b', 'c', 1, 2, 3])
     end
   end
 
   describe 'array difference exercise' do
 
-    xit 'returns an array subtracting two arrays of numbers' do
+    it 'returns an array subtracting two arrays of numbers' do
       expect(array_difference([0, 1, 1, 2, 3, 5], [0, 1, 2])).to eq([3, 5])
     end
 
-    xit 'returns an array subtracting two arrays of strings' do
+    it 'returns an array subtracting two arrays of strings' do
       expect(array_difference(['foo', 'bar', 'baz'], ['bar','hello'])).to eq(['foo', 'baz'])
     end
   end
 
   describe 'empty array exercise' do
 
-    xit 'returns true when the array is empty' do
+    it 'returns true when the array is empty' do
       expect(empty_array?([])).to be true
     end
 
-    xit 'returns false when the array is not empty' do
+    it 'returns false when the array is not empty' do
       expect(empty_array?([1, 2, 3])).to be false
     end
   end
 
   describe 'reverse exercise' do
 
-    xit 'returns an array containing the elements in reverse order' do
+    it 'returns an array containing the elements in reverse order' do
       expect(reverse([0, 1, 1, 2, 3, 5])).to eq([5, 3, 2, 1, 1, 0])
     end
 
-    xit 'returns an array containing the element when there is only one' do
+    it 'returns an array containing the element when there is only one' do
       expect(reverse(['foo'])).to eq(['foo'])
     end
   end
 
   describe 'array length exercise' do
 
-    xit 'returns the length of the array' do
+    it 'returns the length of the array' do
       expect(array_length([0, 1, 1, 2, 3, 5])).to eq(6)
     end
 
-    xit 'returns zero when the array is empty' do
+    it 'returns zero when the array is empty' do
       expect(array_length([])).to eq(0)
     end
   end
 
   describe 'include exercise' do
 
-    xit 'returns true when the array contains the specified value' do
+    it 'returns true when the array contains the specified value' do
       expect(include?([0, 1, 1, 2, 3, 5], 3)).to be true
     end
 
-    xit 'returns false when the array does not contain the specified value' do
+    it 'returns false when the array does not contain the specified value' do
       expect(include?([0, 1, 1, 2, 3, 5], 8)).to be false
     end
   end
 
   describe 'join exercise' do
 
-    xit 'returns a string joining an array of numbers with " + "' do
+    it 'returns a string joining an array of numbers with " + "' do
       expect(join([0, 1, 1, 2, 3, 5], ' + ')).to eq('0 + 1 + 1 + 2 + 3 + 5')
     end
 
-    xit 'returns a string joining an array of strings with " "' do
+    it 'returns a string joining an array of strings with " "' do
       expect(join(['foo', 'bar', 'baz'], ' ')).to eq('foo bar baz')
     end
   end