Merge pull request #1456 from nthitz/randomArray

add random(Array) to get a random element from an array of choices

Author: Lauren McCarthy

src/math/random.js

@@ -76,16 +76,19 @@ p5.prototype.randomSeed = function(seed) {
  * If no argument is given, returns a random number from 0
  * up to (but not including) 1.
  *
- * If one argument is given, returns a random number from 0 up to
- * (but not including) the number.
+ * If one argument is given and it is a number, returns a random number from 0
+ * up to (but not including) the number.
+ *
+ * If one argument is given and it is an array, returns a random element from
+ * that array.
  *
  * If two arguments are given, returns a random number from the
  * first argument up to (but not including) the second argument.
  *
  * @method random
  * @param  {Number} [min]   the lower bound (inclusive)
  * @param  {Number} [max]   the upper bound (exclusive)
- * @return {Number} the random number
+ * @return {Number|mixed} the random number or a random element in choices
  * @example
  * <div>
  * <code>
@@ -106,13 +109,19 @@ p5.prototype.randomSeed = function(seed) {
  * </div>
  * <div>
  * <code>
- * // Get a random element from an array
+ * // Get a random element from an array using the random(Array) syntax
  * var words = [ "apple", "bear", "cat", "dog" ];
- * var index = floor(random(words.length));  // Convert to integer
- * text(words[index],10,50);  // Displays one of the four words
+ * var word = random(words);  // select random word
+ * text(word,10,50);  // draw the word
  * </code>
  * </div>
  */
+/**
+ * @method random
+ * @param  {Array} choices   the array to choose from
+ * @return {mixed} the random element from the array
+ * @example
+ */
 p5.prototype.random = function (min, max) {
 
   var rand;
@@ -127,7 +136,11 @@ p5.prototype.random = function (min, max) {
     return rand;
   } else
   if (arguments.length === 1) {
-    return rand * min;
+    if (arguments[0] instanceof Array) {
+      return arguments[0][Math.floor(rand * arguments[0].length)];
+    } else {
+      return rand * min;
+    }
   } else {
     if (min > max) {
       var tmp = min;

test/unit/math/random.js

@@ -56,6 +56,13 @@ suite('Random', function() {
         assert.isTrue(result < 10);
       });
     });
+    suite('random(["apple", "pear", "orange", "grape"])', function() {
+      test('should return a fruit', function() {
+        var fruits = ['apple', 'pear', 'orange', 'grape'];
+        result = random(fruits);
+        assert.include(fruits, result);
+      });
+    });
   });
 
 });