Add matrix (#336)

Author: BNAndras

config.json

@@ -279,6 +279,14 @@
           "pattern_recognition"
         ]
       },
+      {
+        "slug": "matrix",
+        "name": "Matrix",
+        "uuid": "653ae967-32d2-4789-bb43-289ad1572191",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 2
+      },
       {
         "slug": "matching-brackets",
         "name": "Matching Brackets",

exercises/practice/matrix/.docs/instructions.md

@@ -0,0 +1,38 @@
+# Instructions
+
+Given a string representing a matrix of numbers, return the rows and columns of that matrix.
+
+So given a string with embedded newlines like:
+
+```text
+9 8 7
+5 3 2
+6 6 7
+```
+
+representing this matrix:
+
+```text
+    1  2  3
+  |---------
+1 | 9  8  7
+2 | 5  3  2
+3 | 6  6  7
+```
+
+your code should be able to spit out:
+
+- A list of the rows, reading each row left-to-right while moving top-to-bottom across the rows,
+- A list of the columns, reading each column top-to-bottom while moving from left-to-right.
+
+The rows for our example matrix:
+
+- 9, 8, 7
+- 5, 3, 2
+- 6, 6, 7
+
+And its columns:
+
+- 9, 5, 6
+- 8, 3, 6
+- 7, 2, 7

exercises/practice/matrix/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "BNAndras"
+  ],
+  "files": {
+    "solution": [
+      "matrix.coffee"
+    ],
+    "test": [
+      "matrix.spec.coffee"
+    ],
+    "example": [
+      ".meta/example.coffee"
+    ]
+  },
+  "blurb": "Given a string representing a matrix of numbers, return the rows and columns of that matrix.",
+  "source": "Exercise by the JumpstartLab team for students at The Turing School of Software and Design.",
+  "source_url": "https://turing.edu"
+}

exercises/practice/matrix/.meta/example.coffee

@@ -0,0 +1,12 @@
+class Matrix
+  constructor: (description) ->
+    @rows = description.split("\n").map (row) ->
+      row.split(" ").map (number) -> +number
+
+  row: (index) ->
+    @rows[index - 1]
+
+  column: (index) ->
+    @rows.map (row) -> row[index - 1]
+
+module.exports = Matrix

exercises/practice/matrix/.meta/tests.toml

@@ -0,0 +1,34 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[ca733dab-9d85-4065-9ef6-a880a951dafd]
+description = "extract row from one number matrix"
+
+[5c93ec93-80e1-4268-9fc2-63bc7d23385c]
+description = "can extract row"
+
+[2f1aad89-ad0f-4bd2-9919-99a8bff0305a]
+description = "extract row where numbers have different widths"
+
+[68f7f6ba-57e2-4e87-82d0-ad09889b5204]
+description = "can extract row from non-square matrix with no corresponding column"
+
+[e8c74391-c93b-4aed-8bfe-f3c9beb89ebb]
+description = "extract column from one number matrix"
+
+[7136bdbd-b3dc-48c4-a10c-8230976d3727]
+description = "can extract column"
+
+[ad64f8d7-bba6-4182-8adf-0c14de3d0eca]
+description = "can extract column from non-square matrix with no corresponding row"
+
+[9eddfa5c-8474-440e-ae0a-f018c2a0dd89]
+description = "extract column where numbers have different widths"

exercises/practice/matrix/matrix.coffee

@@ -0,0 +1,8 @@
+class Matrix
+  constructor: (description) ->
+
+  row: (index) ->
+
+  column: (index) ->
+
+module.exports = Matrix

exercises/practice/matrix/matrix.spec.coffee

@@ -0,0 +1,34 @@
+Matrix = require './matrix'
+
+describe 'Matrix', ->
+    it 'extract row from one number matrix', ->
+      matrix = new Matrix "1"
+      expect(matrix.row 1).toEqual [1]
+
+    xit 'can extract row', ->
+      matrix = new Matrix "1 2\n3 4"
+      expect(matrix.row 2).toEqual [3, 4]
+
+    xit 'extract row where numbers have different widths', ->
+      matrix = new Matrix "1 2\n10 20"
+      expect(matrix.row 2).toEqual [10, 20]
+
+    xit 'can extract row from non-square matrix with no corresponding column', ->
+      matrix = new Matrix "1 2 3\n4 5 6\n7 8 9\n8 7 6"
+      expect(matrix.row 4).toEqual [8, 7, 6]
+
+    xit 'extract column from one number matrix', ->
+      matrix = new Matrix "1"
+      expect(matrix.column 1).toEqual [1]
+
+    xit 'can extract column', ->
+      matrix = new Matrix "1 2 3\n4 5 6\n7 8 9"
+      expect(matrix.column 3).toEqual [3, 6, 9]
+
+    xit 'can extract column from non-square matrix with no corresponding row', ->
+      matrix = new Matrix "1 2 3 4\n5 6 7 8\n9 8 7 6"
+      expect(matrix.column 4).toEqual [4, 8, 6]
+
+    xit 'extract column where numbers have different widths', ->
+      matrix = new Matrix "89 1903 3\n18 3 1\n9 4 800"
+      expect(matrix.column 2).toEqual [1903, 3, 4]