Add resistor-color-duo exercise

config.json

@@ -736,6 +736,14 @@
         "practices": [],
         "prerequisites": [],
         "difficulty": 2
+      },
+      {
+        "slug": "resistor-color-duo",
+        "name": "Resistor Color Duo",
+        "uuid": "a118a447-f41d-4904-8dfa-15f45ba3a990",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 1
       }
     ]
   },

exercises/practice/resistor-color-duo/.docs/instructions.md

@@ -0,0 +1,33 @@
+# Instructions
+
+If you want to build something using a Raspberry Pi, you'll probably use _resistors_.
+For this exercise, you need to know two things about them:
+
+- Each resistor has a resistance value.
+- Resistors are small - so small in fact that if you printed the resistance value on them, it would be hard to read.
+
+To get around this problem, manufacturers print color-coded bands onto the resistors to denote their resistance values.
+Each band has a position and a numeric value.
+
+The first 2 bands of a resistor have a simple encoding scheme: each color maps to a single number.
+For example, if they printed a brown band (value 1) followed by a green band (value 5), it would translate to the number 15.
+
+In this exercise you are going to create a helpful program so that you don't have to remember the values of the bands.
+The program will take color names as input and output a two digit number, even if the input is more than two colors!
+
+The band colors are encoded as follows:
+
+- black: 0
+- brown: 1
+- red: 2
+- orange: 3
+- yellow: 4
+- green: 5
+- blue: 6
+- violet: 7
+- grey: 8
+- white: 9
+
+From the example above:
+brown-green should return 15, and
+brown-green-violet should return 15 too, ignoring the third color.

exercises/practice/resistor-color-duo/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "erikschierboom"
+  ],
+  "files": {
+    "solution": [
+      "resistor-color-duo.R"
+    ],
+    "test": [
+      "test_resistor-color-duo.R"
+    ],
+    "example": [
+      ".meta/example.R"
+    ]
+  },
+  "blurb": "Convert color codes, as used on resistors, to a numeric value.",
+  "source": "Maud de Vries, Erik Schierboom",
+  "source_url": "https://github.com/exercism/problem-specifications/issues/1464"
+}

exercises/practice/resistor-color-duo/.meta/example.R

@@ -0,0 +1,5 @@
+colors <- c("black", "brown", "red", "orange", "yellow", "green", "blue", "violet", "grey", "white") # nolint
+
+value <- function(resistor_colors) {
+  sum((match(resistor_colors[1:2], colors) - 1) * c(10, 1))
+}

exercises/practice/resistor-color-duo/.meta/tests.toml

@@ -0,0 +1,31 @@
+# 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.
+
+[ce11995a-5b93-4950-a5e9-93423693b2fc]
+description = "Brown and black"
+
+[7bf82f7a-af23-48ba-a97d-38d59406a920]
+description = "Blue and grey"
+
+[f1886361-fdfd-4693-acf8-46726fe24e0c]
+description = "Yellow and violet"
+
+[b7a6cbd2-ae3c-470a-93eb-56670b305640]
+description = "White and red"
+
+[77a8293d-2a83-4016-b1af-991acc12b9fe]
+description = "Orange and orange"
+
+[0c4fb44f-db7c-4d03-afa8-054350f156a8]
+description = "Ignore additional colors"
+
+[4a8ceec5-0ab4-4904-88a4-daf953a5e818]
+description = "Black and brown, one-digit"

exercises/practice/resistor-color-duo/resistor-color-duo.R

@@ -0,0 +1,3 @@
+value <- function(resistor_colors) {
+
+}

exercises/practice/resistor-color-duo/test_resistor-color-duo.R

@@ -0,0 +1,30 @@
+source("./resistor-color-duo.R")
+library(testthat)
+
+test_that("Brown and black", {
+  expect_equal(value(c("brown", "black")), 10)
+})
+
+test_that("Blue and grey", {
+  expect_equal(value(c("blue", "grey")), 68)
+})
+
+test_that("Yellow and violet", {
+  expect_equal(value(c("yellow", "violet")), 47)
+})
+
+test_that("White and red", {
+  expect_equal(value(c("white", "red")), 92)
+})
+
+test_that("Orange and orange", {
+  expect_equal(value(c("orange", "orange")), 33)
+})
+
+test_that("Ignore additional colors", {
+  expect_equal(value(c("green", "brown", "orange")), 51)
+})
+
+test_that("Black and brown one digit", {
+  expect_equal(value(c("black", "brown")), 1)
+})