Star Pattern Programs in Python

1. Left-Aligned Triangle

*
**
***
****
*****

n = 5
for i in range(1, n + 1):
    print('*' * i)

Explanation:

n = 5: We want 5 lines in the triangle.
range(1, n + 1) → loop will run from 1 to 5 (inclusive).
On each iteration, '*' * i prints i stars.
So output lines increase: 1 star, 2 stars, ..., up to 5 stars.

2. Inverted Left-Aligned Triangle

*****
****
***
**
*

n = 5
for i in range(n, 0, -1):
    print('*' * i)

Explanation:

range(n, 0, -1) → loops backward from 5 to 1.
In each iteration, '*' * i prints decreasing stars.
Output: Starts from 5 stars and decreases line by line.

3. Right-Aligned Triangle

    *
   **
  ***
 ****
*****

n = 5
for i in range(1, n + 1):
    print(' ' * (n - i) + '*' * i)

Explanation:

' ' * (n - i) → Adds spaces before stars for right alignment.
'*' * i → Number of stars in the current row.
As i increases, spaces decrease and stars increase.

4. Right-Aligned Inverted Triangle

*****
 ****
  ***
   **
    *

n = 5
for i in range(n):
    print(' ' * i + '*' * (n - i))

Explanation:

' ' * i → Spaces increase on each row.
'*' * (n - i) → Stars decrease each time.
So triangle shifts right and shrinks line by line.

5. Pyramid Pattern

    *
   ***
  *****
 *******
*********

n = 5
for i in range(n):
    print(' ' * (n - i - 1) + '*' * (2 * i + 1))

Explanation:

' ' * (n - i - 1) → Center align by adding spaces.
'*' * (2 * i + 1) → Stars increase by odd numbers (1, 3, 5...).
Each row forms a centered pyramid layer.

6. Inverted Pyramid

*********
 *******
  *****
   ***
    *

n = 5
for i in range(n):
    print(' ' * i + '*' * (2 * (n - i) - 1))

Explanation:

' ' * i → Spaces increase down the rows.
'*' * (2 * (n - i) - 1) → Stars decrease as row increases.
Reverse of normal pyramid.

7. Diamond Pattern

    *
   ***
  *****
 *******
*********
 *******
  *****
   ***
    *

n = 5
for i in range(n):
    print(' ' * (n - i - 1) + '*' * (2 * i + 1))
for i in range(n - 2, -1, -1):
    print(' ' * (n - i - 1) + '*' * (2 * i + 1))

Explanation:

First loop prints normal pyramid.
Second loop (reverse) prints inverted pyramid.
Together they form a diamond shape.

8. Hollow Square Pattern

*****
*   *
*   *
*   *
*****

n = 5
for i in range(n):
    if i == 0 or i == n - 1:
        print('*' * n)
    else:
        print('*' + ' ' * (n - 2) + '*')

Explanation:

Top and bottom lines are full of stars.
Middle lines have star at start and end, spaces in between.
Forms a hollow box.

9. Star Pyramid (Like Number Pyramid but with Stars)

    *
   * *
  * * *
 * * * *
* * * * *

n = 5
for i in range(1, n + 1):
    print(' ' * (n - i), end='')
    for j in range(i):
        print('* ', end='')
    print()

Explanation:

Spaces before stars align the pyramid center.
Each row prints i stars with a space after each.
Output forms a centered star pyramid.

10. Hollow Pyramid

    *
   * *
  *   *
 *     *
*********

n = 5
for i in range(n):
    for j in range(n - i - 1):
        print(' ', end='')
    for j in range(2 * i + 1):
        if j == 0 or j == 2 * i or i == n - 1:
            print('*', end='')
        else:
            print(' ', end='')
    print()

Explanation:

Outer loop builds each row.
First inner loop adds spaces to center align.
Second loop adds stars only at borders and full bottom line.
Middle of pyramid is hollow.

Star Pattern Python Programs

1. Left-Aligned Triangle

2. Inverted Left-Aligned Triangle

3. Right-Aligned Triangle

4. Right-Aligned Inverted Triangle

5. Pyramid Pattern

6. Inverted Pyramid

7. Diamond Pattern

8. Hollow Square Pattern

9. Star Pyramid (Like Number Pyramid but with Stars)

10. Hollow Pyramid