## Python 3 Heap Sort Algorithm Script to Sort Number Array in Ascending or Descending Order Full Example Project For Beginners

Welcome folks today in this blog post we will be `sorting number array in ascending or descending order using heap sort algorithm` in python. All the full source code of the application is shown below.

# Get Started

In order to get started you need to make an `app.py` file and copy paste the following code

`app.py`

``````# Python program for implementation of heap Sort

# To heapify subtree rooted at index i.
# n is size of heap
def heapify(arr, n, i):
largest = i # Initialize largest as root
l = 2 * i + 1    # left = 2*i + 1
r = 2 * i + 2    # right = 2*i + 2

# See if left child of root exists and is
# greater than root
if l < n and arr[i] < arr[l]:
largest = l

# See if right child of root exists and is
# greater than root
if r < n and arr[largest] < arr[r]:
largest = r

# Change root, if needed
if largest != i:
arr[i],arr[largest] = arr[largest],arr[i] # swap

# Heapify the root.
heapify(arr, n, largest)

# The main function to sort an array of given size
def heapSort(arr):
n = len(arr)

# Build a maxheap.
# Since last parent will be at ((n//2)-1) we can start at that location.
for i in range(n // 2 - 1, -1, -1):
heapify(arr, n, i)

# One by one extract elements
for i in range(n-1, 0, -1):
arr[i], arr[0] = arr[0], arr[i] # swap
heapify(arr, i, 0)

# Driver code to test above
arr = [ 12, 11, 13, 5, 6, 7]
heapSort(arr)
n = len(arr)
print ("Sorted array is")
for i in range(n):
print ("%d" %arr[i]),
# This code is contributed by Mohit Kumra``````

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Now if you execute the `python file` script by typing the below command as shown below

`python app.py`