Implementation of Matrix problem

lib/matrix.rb

@@ -0,0 +1,27 @@
+class Matrix
+  @matrix
+
+  def initialize(string)
+    @matrix = string
+  end
+
+  def extract_row(row_number)
+    array = []
+    rows_of_matrix = @matrix.split("\n")
+    selected_row = rows_of_matrix[row_number]
+    selected_row.split(" ").each do |string|
+      array << string.to_i
+    end
+    array
+  end
+
+  def extract_column(column_number)
+    array = []
+    rows_of_matrix = @matrix.split("\n")
+    rows_of_matrix.each do |row|
+      array << row.split(" ")[column_number].to_i
+    end
+    array
+  end
+
+end

spec/matrix_spec.rb

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+require 'matrix.rb'
+describe Matrix do
+
+  context "when extracting a row of a matrix" do
+    it "returns [1, 2] as the first row of the matrix" do
+      matrix = Matrix.new("1 2\n10 20")
+      expect(matrix.extract_row(0)).to eq([1, 2])
+    end
+
+    it "returns [8, 6] as the second row of the matrix" do
+      matrix = Matrix.new("9 7\n8 6")
+      expect(matrix.extract_row(1)).to eq([8, 6])
+    end
+
+    it "returns [9, 8, 7] as the first row of the matrix" do
+      matrix = Matrix.new("9 8 7\n19 18 17")
+      expect(matrix.extract_row(0)).to eq([9, 8, 7])
+    end
+  end
+
+  context "when extracting a column of a matrix" do
+    it "returns [1 , 10] as the first column of the matrix" do
+      matrix = Matrix.new("1 2\n10 20")
+      expect(matrix.extract_column(0)).to eq([1, 10])
+    end
+
+    it "returns [5 , 20] as the second column of the matrix" do
+      matrix = Matrix.new("4 5\n19 20")
+      expect(matrix.extract_column(1)).to eq([5, 20])
+    end
+
+    it "returns [19, 13] as the second column of the non-regular matrix" do
+      matrix = Matrix.new("10 19 15\n11 13 16")
+      expect(matrix.extract_column(1)).to eq([19, 13])
+    end
+  end
+end
+