How to Make an Insertion Sort in Python

Python is an ideal programming language for beginners due to its natural language syntax, easy-to-follow indented code and flexible data types that are not interpreted until needed. When programming in Python, you may need to sort data. An insertion sort is a basic sort where Python starts at the beginning of an array and sorts through it one element at a time. Elements are sorted relative to each other during each iteration.

Instructions

1. Access your Python editor, and open your program.

2. Define the insertion sort routine. For example, define the insertion sort for sorting student test scores:

   def InsertionSort (scores)

3. Create the loop to sort through the array of scores. For example, type:

   for n in range (1, len(scores)):
   key = scores [n]
   i = n -1
   while (i > = 0) and (scores [1] > key) :
   scores [ i+1] = scores [ i ]
   i = i -1
   scores [ i +1] = key

4. Save your program and test it. Continuing the example, type the following and pressing "Enter."

   TestScores = [86, 55, 92, 67, 75, 83, 95 ]

5. Call the insertion sort routine by typing the following and pressing "Enter."

   InsertionSort (TestScores)

   Python sorts the list of test scores in ascending order. In this example, Python returns:

   [ 55, 67, 75, 83, 86, 92, 95 ]

References

• Department of Engineering and Computer Engineering - University of California, Irvine