interator / generators exmaples

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+
+# here is a simple generator
+# a 'yield' returns an expression which then gets invoked in for loop, a num by itself is an expression
+def gen1():
+    yield 1
+    yield 2
+    yield 3  # at this point python's list implemention will raise StopIteration since were at last yield
+
+a = [i for i in gen1()]
+print(a)
+
+
+# following example depicts how Comprehensions are syntactically almost the same except the use of () instead of []
+
+gen2 = ("{0} is even".format(i) for i in range(0, 10) if i % 2 == 0)
+print(gen2.__next__())  # get a value
+print(list(gen2))  # loop till the end
+#print(gen2.__next__())  # this would error, generator can only be looped once
+
+# output
+#
+# 0 is even
+# ['2 is even', '4 is even', '6 is even', '8 is even']
+
+
+
+# here is a Generator version of string reversal from interator.py
+
+def reverseString2(data):
+    for index in range(len(data) - 1, -1, -1):
+        yield data[index]
+
+for c in reverseString2('barfoo'):
+    print(c)