Update average_median.py (#998)

added doctest, fixed TypeError: list indices must be integers or slices, not float error due to number/2 producing float as index.

maths/average_median.py

@@ -1,41 +1,34 @@
-"""
-Find median of a list of numbers.
-
-Read more about medians:
-    https://en.wikipedia.org/wiki/Median
-"""
-
-
 def median(nums):
-    """Find median of a list of numbers."""
-    # Sort list
-    sorted_list = sorted(nums)
-    print("List of numbers:")
-    print(sorted_list)
+    """
+    Find median of a list of numbers.
 
-    # Is number of items in list even?
+    >>> median([0])
+    0
+    >>> median([4,1,3,2])
+    2.5
+
+    Args:
+        nums: List of nums
+
+    Returns:
+        Median.
+    """
+    sorted_list = sorted(nums)
+    med = None
     if len(sorted_list) % 2 == 0:
-        # Find index for first middle value.
-        mid_index_1 = len(sorted_list) / 2
-        # Find index for second middle value.
-        mid_index_2 = -(len(sorted_list) / 2) - 1
-        # Divide middle values by 2 to get average (mean).
+        mid_index_1 = len(sorted_list) // 2
+        mid_index_2 = (len(sorted_list) // 2) - 1
         med = (sorted_list[mid_index_1] + sorted_list[mid_index_2]) / float(2)
-        return med  # Return makes `else:` unnecessary.
-    # Number of items is odd.
-    mid_index = (len(sorted_list) - 1) / 2
-    # Middle index is median.
-    med = sorted_list[mid_index]
+    else:
+        mid_index = (len(sorted_list) - 1) // 2
+        med = sorted_list[mid_index]
     return med
 
-
 def main():
-    """Call average module to find median of a specific list of numbers."""
     print("Odd number of numbers:")
     print(median([2, 4, 6, 8, 20, 50, 70]))
     print("Even number of numbers:")
     print(median([2, 4, 6, 8, 20, 50]))
 
-
 if __name__ == '__main__':
     main()