Add U.takeSkipping(iterable, stepSize) method.

Author: Szkocsovszki

src/main/java/com/github/underscore/U.java

@@ -2960,6 +2960,10 @@ public Chain<List<T>> splitAt(final int position) {
             return new Chain<List<T>>(U.splitAt(list, position));
         }
 
+        public Chain<T> takeSkipping(final int stepSize) {
+            return new Chain<T>(U.takeSkipping(list, stepSize));
+        }
+
         public Chain<T> reverse() {
             return new Chain<T>(U.reverse(list));
         }
@@ -3274,6 +3278,33 @@ public List<List<T>> splitAt(final int position) {
         return splitAt(iterable, position);
     }
 
+    public static <T> List<T> takeSkipping(final Iterable<T> iterable, final int stepSize) {
+        List<T> result = newArrayList();
+        if (stepSize <= 0) {
+            return result;
+        }
+        int size = size(iterable);
+        if (stepSize > size) {
+            result.add(first(iterable));
+            return result;
+        }
+        int i = 0;
+        for (T element : iterable) {
+            if (i++ % stepSize == 0) {
+                result.add(element);
+            }
+        }
+        return result;
+    }
+
+    public static <T> List<T> takeSkipping(final T[] array, final int stepSize) {
+        return takeSkipping(Arrays.asList(array), stepSize);
+    }
+
+    public List<T> takeSkipping(final int stepSize) {
+        return takeSkipping(iterable, stepSize);
+    }
+
     /*
      * Documented, #reverse
      */

src/test/java/com/github/underscore/UnderscoreTest.java

@@ -215,6 +215,29 @@ public void splitAt() {
         assertEquals("[[0, 1], [2, 3, 4]]", U.splitAt(array, 2).toString());
     }
 
+/*
+_.takeSkipping([1, 2, 3, 4, 5], 2);
+=> [0, 2, 4]
+_.takeSkipping([1, 2, 3, 4, 5], 100000);
+=> [0]
+_.takeSkipping([1, 2, 3, 4, 5], -100);
+=> []
+*/
+    @Test
+    public void takeSkipping() {
+        assertEquals("[0, 2, 4]", U.takeSkipping(U.newIntegerList(U.range(5)), 2).toString());
+        assertEquals("[0]", U.takeSkipping(U.newIntegerList(U.range(5)), 100000).toString());
+        assertEquals("[]", U.takeSkipping(U.newIntegerList(U.range(5)), -100).toString());
+        assertEquals("[]", U.takeSkipping(U.newIntegerList(U.range(5)), 0).toString());
+        assertEquals("[0, 2, 4]", new U<Integer>(U.newIntegerList(U.range(5))).takeSkipping(2).toString());
+        assertEquals("[0, 2, 4]", U.chain(U.newIntegerList(U.range(5))).takeSkipping(2).value().toString());
+        assertEquals("[a, c, e]", U.takeSkipping(asList('a', 'b', 'c', 'd', 'e'), 2).toString());
+        assertEquals("[ant, camel, elephant]", U.takeSkipping(asList("ant", "bird", "camel", "dog", "elephant"), 2).toString());
+        assertEquals("[0.1, 0.3, 0.5]", U.takeSkipping(asList(0.1, 0.2, 0.3, 0.4, 0.5), 2).toString());
+        final Integer[] array = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
+        assertEquals("[0, 3, 6, 9]", U.takeSkipping(array, 3).toString());
+    }
+
 /*
 var arr = [ 1, 2, 3 ]
 _.copyOf(arr) // => [1, 2, 3]