sync to Atlas repo

iterables/aritprog_v1.py

@@ -0,0 +1,48 @@
+"""
+Arithmetic progression class
+
+    >>> ap = ArithmeticProgression(1, .5, 3)
+    >>> list(ap)
+    [1.0, 1.5, 2.0, 2.5]
+
+
+"""
+
+import array
+from collections import abc
+
+class ArithmeticProgression:
+
+    def __init__(self, begin, step, end):
+        self.begin = begin
+        self.step = step
+        self.end = end
+        self._build()
+
+    def _build(self):
+        self._numbers = array.array('d')
+        n = self.begin
+        while n < self.end:
+            self._numbers.append(n)
+            n += self.step
+
+    def __iter__(self):
+        return ArithmeticProgressionIterator(self._numbers)
+
+
+class ArithmeticProgressionIterator(abc.Iterator):
+
+    def __init__(self, series):
+        self._series = series
+        self._index = 0
+
+    def __next__(self):
+        if self._index < len(self._series):
+            item = self._series[self._index]
+            self._index += 1
+            return item
+        else:
+            raise StopIteration
+
+
+