Fixed typos and added the shell sort algorithm

sorts/bogosort.py

@@ -1,5 +1,5 @@
 """
-This is pure python implementation of bogosort algorithm
+This is pure python implementation of the bogosort algorithm
 For doctests run following command:
 python -m doctest -v bogosort.py
 or
@@ -47,6 +47,6 @@ if __name__ == '__main__':
     else:
         input_function = input
 
-    user_input = input_function('Enter numbers separated by coma:\n')
+    user_input = input_function('Enter numbers separated by a comma:\n')
     unsorted = [int(item) for item in user_input.split(',')]
     print(bogosort(unsorted))

sorts/bubble_sort.py

@@ -47,6 +47,6 @@ if __name__ == '__main__':
     else:
         input_function = input
 
-    user_input = input_function('Enter numbers separated by coma:\n')
+    user_input = input_function('Enter numbers separated by a comma:\n')
     unsorted = [int(item) for item in user_input.split(',')]
     print(bubble_sort(unsorted))

sorts/heap_sort.py

@@ -1,4 +1,14 @@
+"""
+This is a pure python implementation of the heap sort algorithm.
 
+For doctests run following command:
+python -m doctest -v insertion_sort.py
+or
+python3 -m doctest -v insertion_sort.py
+
+For manual testing run:
+python insertion_sort.py
+"""
 from  __future__ import print_function
 
 
@@ -17,6 +27,21 @@ def heapify(unsorted,index,heap_size):
 		heapify(unsorted,largest,heap_size)		
 		
 def heap_sort(unsorted):	
+    """Pure implementation of the heap sort algorithm in Python
+    :param collection: some mutable ordered collection with heterogeneous
+    comparable items inside
+    :return: the same collection ordered by ascending
+
+    Examples:
+    >>> heap_sort([0, 5, 3, 2, 2])
+    [0, 2, 2, 3, 5]
+
+    >>> heap_sort([])
+    []
+
+    >>> heap_sort([-2, -5, -45])
+    [-45, -5, -2]
+    """
 	n=len(unsorted) 
 	for i in range (n/2 - 1 , -1, -1) :
 		heapify(unsorted,i,n)
@@ -33,7 +58,7 @@ if __name__ == '__main__':
     else:
         input_function = input
 
-    user_input = input_function('Enter numbers separated by coma:\n')
+    user_input = input_function('Enter numbers separated by a comma:\n')
     unsorted = [int(item) for item in user_input.split(',')]
     print (heap_sort(unsorted))
 

sorts/insertion_sort.py

@@ -1,5 +1,5 @@
 """
-This is pure python implementation of insertion sort algorithm
+This is a pure python implementation of the insertion sort algorithm
 
 For doctests run following command:
 python -m doctest -v insertion_sort.py
@@ -13,7 +13,7 @@ from __future__ import print_function
 
 
 def insertion_sort(collection):
-    """Pure implementation of insertion sort algorithm in Python
+    """Pure implementation of the insertion sort algorithm in Python
 
     :param collection: some mutable ordered collection with heterogeneous
     comparable items inside
@@ -51,6 +51,6 @@ if __name__ == '__main__':
     else:
         input_function = input
 
-    user_input = input_function('Enter numbers separated by coma:\n')
+    user_input = input_function('Enter numbers separated by a comma:\n')
     unsorted = [int(item) for item in user_input.split(',')]
     print(insertion_sort(unsorted))

sorts/merge_sort.py

@@ -1,5 +1,5 @@
 """
-This is pure python implementation of merge sort algorithm
+This is a pure python implementation of the merge sort algorithm
 
 For doctests run following command:
 python -m doctest -v merge_sort.py
@@ -13,7 +13,7 @@ from __future__ import print_function
 
 
 def merge_sort(collection):
-    """Pure implementation of merge sort algorithm in Python
+    """Pure implementation of the merge sort algorithm in Python
 
     :param collection: some mutable ordered collection with heterogeneous
     comparable items inside
@@ -71,6 +71,6 @@ if __name__ == '__main__':
     else:
         input_function = input
 
-    user_input = input_function('Enter numbers separated by coma:\n')
+    user_input = input_function('Enter numbers separated by a comma:\n')
     unsorted = [int(item) for item in user_input.split(',')]
     print(merge_sort(unsorted))

sorts/quick_sort.py

@@ -1,5 +1,5 @@
 """
-This is pure python implementation of quick sort algorithm
+This is a pure python implementation of the quick sort algorithm
 
 For doctests run following command:
 python -m doctest -v quick_sort.py
@@ -62,6 +62,6 @@ if __name__ == '__main__':
     else:
         input_function = input
 
-    user_input = input_function('Enter numbers separated by coma:\n')
+    user_input = input_function('Enter numbers separated by a comma:\n')
     unsorted = [int(item) for item in user_input.split(',')]
     print(sort(unsorted))

sorts/selection_sort.py

@@ -1,5 +1,5 @@
 """
-This is pure python implementation of selection sort algorithm
+This is a pure python implementation of the selection sort algorithm
 
 For doctests run following command:
 python -m doctest -v selection_sort.py
@@ -13,7 +13,11 @@ from __future__ import print_function
 
 
 def selection_sort(collection):
-    """Pure implementation of selection sort algorithm in Python
+    """Pure implementation of the selection sort algorithm in Python
+    :param collection: some mutable ordered collection with heterogeneous
+    comparable items inside
+    :return: the same collection ordered by ascending
+    
 
     Examples:
     >>> selection_sort([0, 5, 3, 2, 2])
@@ -24,11 +28,8 @@ def selection_sort(collection):
 
     >>> selection_sort([-2, -5, -45])
     [-45, -5, -2]
-
-    :param collection: some mutable ordered collection with heterogeneous
-    comparable items inside
-    :return: the same collection ordered by ascending
     """
+   
     length = len(collection)
     for i in range(length):
         least = i
@@ -50,6 +51,6 @@ if __name__ == '__main__':
     else:
         input_function = input
 
-    user_input = input_function('Enter numbers separated by coma:\n')
+    user_input = input_function('Enter numbers separated by a comma:\n')
     unsorted = [int(item) for item in user_input.split(',')]
     print(selection_sort(unsorted))

sorts/shell_sort.py

@@ -0,0 +1,58 @@
+"""
+This is a pure python implementation of the shell sort algorithm
+
+For doctests run following command:
+python -m doctest -v shell_sort.py
+or
+python3 -m doctest -v shell_sort.py
+
+For manual testing run:
+python shell_sort.py
+"""
+from __future__ import print_function
+
+
+def shell_sort(collection):
+    """Pure implementation of shell sort algorithm in Python
+    :param collection:  Some mutable ordered collection with heterogeneous
+    comparable items inside
+    :return:  the same collection ordered by ascending
+    
+    >>> shell_sort([0, 5, 3, 2, 2)]
+    [0, 2, 2, 3, 5]
+
+    >>> shell_sort([])
+    []
+     
+    >>> shell_sort([-2, -5, -45]) 
+    [-45, -5, -2]
+    """
+    # Marcin Ciura's gap sequence
+    gaps = [701, 301, 132, 57, 23, 10, 4, 1]
+    
+    for gap in gaps:
+        i = gap
+        while i < len(collection):
+            temp = collection[i]
+            j = i
+            while j >= gap and collection[j-gap] > temp:
+                collection[j] = collection[j - gap]
+                j -= gap
+            collection[j] = temp
+            i += 1
+        
+        
+    return collection
+
+if __name__ == '__main__':
+    import sys
+    # For python 2.x and 3.x compatibility: 3.x has not raw_input builtin
+    # otherwise 2.x's input builtin function is too "smart"
+    if sys.version_info.major < 3:
+        input_function = raw_input
+    else:
+        input_function = input
+
+    user_input = input_function('Enter numbers separated by a comma:\n')
+    unsorted = [int(item) for item in user_input.split(',')]
+    print(shell_sort(unsorted))