Python hollow triangle while loop

This python program generates hollow pyramid pattern made up of stars up to n lines.

In this python example, we first read number of row in the hollow pyramid pattern from user using built-in function input(). And then we use using python's for loop to print hollow pyramid pattern.

Python Source Code: Pyramid Pattern

# Generating Hollow Pyramid Pattern Using Stars

row = int(input('Enter number of rows required: '))

for i in range(row):
    for j in range(row-i):
        print(' ', end='') # printing space required and staying in same line
    
    for j in range(2*i+1):
        if j==0 or j==2*i or i==row-1:
            print('*',end='')
        else:
            print(' ', end='')
    print() # printing new line

In this program print() only is used to bring control to new lines.

Output: Pyramid Pattern

Enter number of rows required: 12
            *
           * *
          *   *
         *     *
        *       *
       *         *
      *           *
     *             *
    *               *
   *                 *
  *                   *
 ***********************

Python Pattern Programs using While Loop

In this tutorial, we will learn how to print patterns to console using Python While Loop.

Example 1 – Python Program to Print Right Triangle using While Loop

In this example, we will write a Python program to print the following start pattern to console. We shall read the number of rows and print starts as shown below.

Pattern

For an input number of 4, following would be the pattern.

*
* *
* * *
* * * *

Try Online

Python Program

n = int(input('Enter number of rows : '))

i = 1
while i <= n :
    j = 1
    while j <= i:
        print("*", end = " ")
        j += 1
    print()
    i += 1

Inner while loop prints a single row after its complete execution. Outer while loop helps to print n number of rows.

In other words, outer while loop prints the rows, while inner while loop prints columns in each row.

Output

Enter number of rows : 6
*
* *
* * *
* * * *
* * * * *
* * * * * *

Example 2 – Python Program to Print Inverted Right Triangle using While Loop

In this example, we will write a Python program to print the following start pattern to console.

Pattern

For an input number of 4, following would be the pattern.

* * * *
* * *
* *
*

Try Online

Python Program

n = int(input('Enter number of rows : '))

i = 1
while i <= n :
    j = n
    while j >= i:
        print("*", end = " ")
        j -= 1
    print()
    i += 1

Output

Enter number of rows : 5
* * * * *
* * * *
* * *
* *
*

Example 3 – Python Program to Print Number Pattern using While Loop

In this example, we will write a Python program to print the following pattern to console. We shall read the number of rows and print numbers as shown below.

Pattern

For an input number of 5, following would be the pattern.

1
  2   3
  4   5   6
  7   8   9  10
 11  12  13  14  15

Try Online

Python Program

n = int(input('Enter number of rows : '))

k = 1
i = 1
while i <= n :
    j = 1
    while j <= i:
        print("{:3d}".format(k), end = " ")
        j += 1
        k += 1
    print()
    i += 1

Output

Enter number of rows : 7
  1
  2   3
  4   5   6
  7   8   9  10
 11  12  13  14  15
 16  17  18  19  20  21
 22  23  24  25  26  27  28

Conclusion

In this Python Tutorial, we learned to write Python programs to print different types of patterns using While Loop.