Merge pull request #5 from SergeyTsaplin/selection-sort-python-way

Make selection sort pythonic way

SelectionSort.py

@@ -1,20 +0,0 @@
-def selectionsort( aList ):
-  for i in range( len( aList ) ):
-    least = i
-    for k in range( i + 1 , len( aList ) ):
-      if aList[k] < aList[least]:
-        least = k
- 
-    aList = swap( aList, least, i )
-  print(aList)
- 
-def swap( A, x, y ):
-  tmp = A[x]
-  A[x] = A[y]
-  A[y] = tmp
-  return A
-
-print ("Enter numbers seprated by comma ")
-response = input()
-aList = [int(item) for item in (response.split(','))]
-selectionsort(aList)

selection_sort.py

@@ -0,0 +1,51 @@
+"""
+This is pure python implementation of selection sort algorithm
+
+For doctests run following command:
+python -m doctest -v selection_sort.py
+or
+python3 -m doctest -v selection_sort.py
+"""
+from __future__ import print_function
+
+def selection_sort(sortable):
+    """Pure implementation of selection sort algorithm in Python
+
+    Examples:
+    >>> selection_sort([0, 5, 3, 2, 2])
+    [0, 2, 2, 3, 5]
+
+    >>> selection_sort([])
+    []
+
+    >>> selection_sort([-2, -5, -45])
+    [-45, -5, -2]
+
+    :param sortable: some mutable ordered collection with heterogeneous
+    comparable items inside
+    :return: the same collection ordered by ascending
+    """
+    length = len(sortable)
+    for i in range(length):
+        least = i
+        for k in range(i + 1, length):
+            if sortable[k] < sortable[least]:
+                least = k
+        sortable[least], sortable[i] = (
+            sortable[i], sortable[least]
+        )
+    return sortable
+
+
+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 coma:\n')
+    unsorted = [int(item) for item in user_input.split(',')]
+    print(selection_sort(unsorted))