Python Tutorial

def hollow_pyramid( r ) :
    m = 0
    for n in range(1, r + 1) : # last row
     
        # printing spaces
        for p in range(n , r) :
            print(' ', end='')
         
        # Print *
        while (m != (2 * n - 1)) :
            if (m == 0 or m == 2 * n - 2) :
                print('*', end='')
            else :
                print(' ', end ='')
            m = m + 1
        m = 0;
        print ("")  # printing next row
         
    # printing last row
    for n in range(0, 2 * r -1) :
        print ('*', end = '')
 
# displaying the pyramid
r = 8
hollow_pyramid(r)

Output:

Explanation:

This hollow pyramid pattern can be made with any symbol like * or #. We have made this hollow pyramid using nested loops with the character '*'. We have printed 2 * r - 1 (r is the number of rows in the pattern) '*' characters in the last row. The number of rows can also be changed.

This hollow pyramid can be made using another method using for loops and elif conditions:

Method 2:

Code:

def hollow_pyramid(r):
    for k in range(r):
        for i in range ( r - k):
        # left spaces in the same row
            print(' ', end='')

        for i in range(2 * k + 1):
        # printing the left side boundary of the pyramid
            if i == 0:
                print('*', end='')

        # The right-side boundary of the pyramid
            elif i == 2 * k:
                print('*', end='')

        # The bottom line of the pyramid
            elif k == r - 1:
                print('*', end='')

        # spaces in the middle of the pyramid
            else:
                print(' ', end='')

        print()      # new line
r = 8
hollow_pyramid(r)

Output:

Explanation:

This hollow pyramid pattern is similar to the above one, but the pattern's formation process differs. We have used elif statements to print the character '*' in the hollow pyramid.

We can make this basic hollow pyramid pattern using only while function also.

Code:

def hollow_pyramid2 (row):
   n = 1 
   while n<= row: 
      if n == 1: 
         # printing the spaces in the pyramid
         print(" " * (row - n) + "*")
      elif n == row: 
         # print the stars of the pyramid
         print("* " * n)
      else: 
         # print the spaces and stars together
         print(" " * (row - n) + "*" + " " * (2*n-3) + "*")
      n+=1

# taking input from the user
row = int(input('Enter number of rows: '))

# calling the function
hollow_pyramid2 (row)

Output:

Explanation:

This hollow pyramid is made using while loops. In this, the user takes the number of rows as input. It is a short and simple method to print the basic hollow pyramid.

There can be various patterns and modifications of the hollow pyramid.

Modifications of the hollow pyramid

1. Left half pyramid

Code:

def left_hollow_pyramid(row):
   for i in range(1, row + 1):
      for j in range(i):
         if j == 0 or j == i - 1:
            # stars
            print("*", end=" ")
         else:
            if i != row:
               # spaces
               print(" ", end=" ")
            else:
               
               print("*", end=" ")
      print()
 
# taking input from the user
row = int(input('Enter number of rows: '))

# calling the function 
left_hollow_pyramid(row)

Output:

Explanation:

We have made a left-side half pyramid using loops. The user will give the number of rows as input.

2. Left downward half pyramid

Code:

def downward_left (row):
   for i in range(row, 0, -1):
      for j in range(i, 0, -1):
         if i == 1 or i == row or j == 1 or j == i:
            # print the stars
            print("*", end=" ")
         else:
            # print the spaces
            print(" ", end=" ")
      print()

# taking input from the user
row = int(input('Enter number of rows: '))

# calling the function 
downward_left(row)

Output:

Explanation:

We have made a left-side downward hollow pyramid. In this, a reverse loop prints the downward left-side pyramid.

3. Downward Hollow Pyramid

Code:

def downward_pyramid(row):
   for i in range(1, row + 1):
      for j in range(0, i):
         # spaces in the pyramid
         print(" ", end=" ")

      for j in range(1, (row * 2 - (2 * i - 1)) + 1):
         if i == 1 or j == 1 or j ==(row * 2 - ( 2 * i - 1)):
            
            print("*", end=" ")
         else:
            print(" ", end=" ")
      print()

# taking input from the user
row = int(input('Enter number of rows: '))

# calling the function 
downward_pyramid(row)

Output: