[Python] Challenge 6 (#455)

challenge_6/python/alexbotello/README.md

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+# Ranges
+###### Language Version (Python 3.6.0)
+
+First, we must set a couple of variable flags to keep track of the array
+sequence and initialize our ```ranges``` list. We'll choose ```begin``` and ```end```
+as sufficient flag names. Next, we iterate through the input array and set the
+value of our flags to equal the first element. For every iteration after, if the
+next element is in sequence to the previous, we update our `end` flag to equal
+the current element. Once, we iterate to an element that breaks the sequence we
+append our flag values to our ```ranges``` list and reset flags to the current
+element. Finally, after the for loop is complete, make a final comparison of
+```begin``` and ```end``` to check if a final range sequence exists.
+
+### Compile
+Run ```tests.py``` to check against unit test
+```
+......
+----------------------------------------------------------------------
+Ran 6 tests in 0.001s
+
+OK
+```
+
+Run ```ranges.py``` to test your own implementation
+First input should be the size of your array. Subsequent inputs will be the values
+of the array.
+
+
+Unit Test written by: slandau3

challenge_6/python/alexbotello/src/ranges.py

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+# Ranges
+
+def ranges(int_list):
+    """
+    Given a sorted list of integers function will return
+    an array of strings that represent the ranges
+    """
+    begin = 0
+    end = 0
+
+    ranges = []
+
+    for i in int_list:
+        # At the start of iteration set the value of
+        # `begin` and `end` to equal the first element
+        if begin == 0:
+            begin = i
+            end = i
+        # Set the current element as the value of `end`
+        # as long as the array is in sequence
+        elif i-1 == end:
+            end = i
+        # Reset flags to current element when iterating through
+        # multiple integers that are of broken sequence
+        elif begin == end:
+            begin = i
+            end = i
+        else:
+        # Sequence of array has been broken, append current range
+        # to `ranges` and set the value of `begin and `end` flags to
+        # equal the current element
+            ranges.append("{0}->{1}".format(begin, end))
+            begin = i
+            end = i
+    # Grab the last range from the array
+    if begin != end:
+        ranges.append("{0}->{1}".format(begin, end))
+
+    return ranges
+
+
+if __name__ == "__main__":
+        # Test your own implementation
+        # Input the size of the array
+        # Then enter each integer value
+        size = int(input())
+        ints = [int(input()) for _ in range(size)]
+        print(ranges(ints))

challenge_6/python/alexbotello/src/tests.py

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+import unittest
+from ranges import ranges
+
+class TestRanges(unittest.TestCase):
+
+    def test1(self):
+        """
+        Tests a basic input that should only have 1 element in the list
+        :return:
+        """
+        self.assertEqual(ranges([1,2]), ['1->2'])
+
+    def test2(self):
+        """
+        Tests a case in which the return value should contain no elements
+        :return:
+        """
+        self.assertEqual(ranges([1]), [])
+
+    def test3(self):
+        self.assertEqual(ranges([1,2,3,4,5,8,9,10]), ['1->5', '8->10'])
+
+    def test4(self):
+        self.assertEqual(ranges([5,6,7,20,21,22,25]), ['5->7', '20->22'])
+
+    def test5(self):
+        self.assertEqual(ranges([5,6,9,10,12,13,15,16,18,19,25,30]), ['5->6', '9->10', '12->13', '15->16', '18->19'])
+
+    def test6(self):
+        self.assertEqual(ranges([5,6,7,10,15,18,20,21,22]), ['5->7', '20->22'])
+
+
+if __name__ == '__main__':
+    unittest.main()