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Generate a hollow equilateral triangle using alphabets in Python

Vinisha Maheshwari

In this shot, we will learn how to generate a hollow equilateral triangle, using alphabets in Python.

We can print a plethora of patterns using Python. The only prerequisite for this is having a good understanding of how loops work in Python. Here, we will use simple for loops and alphabets to generate a hollow equilateral triangle.


A triangle is said to be equilateral if it has all 3 sides of the same length. To create an equilateral triangle with alphabets using Python programming, we will use 2 for loops:

  • An outer Loop: To handle the number of rows.
  • An inner loop: To handle the number of columns.


Let’s look at the code for this:

# Number of Rows
n = 8

if n > 26 or n < 3:
    The value of n should be less than 26 as there are 26 alphabets and 
    \ngreater than 3 as that's the smallest hollow triangle that can be made.
    # Outer loop for rows
    for i in range(1,n+1):
        # Inner loop for columns
        for j in range(1,2*n):
            ch = chr(64+i)
            # Conditions for creating the pattern
            if i==n or i+j==n+1 or j-i==n-1:
                print(ch, end=" ")
                print(end="  ")
            j += 1


In the code given above:

  • In line 2, we take the input for the number of rows.

  • From lines 4–5, we check whether the value of n is less than 26 or greater than 3. If it exceeds 26, then we will not proceed further and print a message. This is done to ensure that only 26 alphabets are used to generate the pattern. Similarly, if the value is less than 3, then the triangle will not be hollow.

  • In line 9, we create a for loop to handle the number of rows.

  • In line 12, we create a nested for loop to handle the number of columns.

  • In line 14, we define ch which is used to create alphabets from numbers by using the iterative value of i and the concept of ASCII conversion. The starting value 64 + (i=1), is used as the ASCII value of A (starting of the triangle), which is 65.

  • From lines 17–22, we define the conditions for creating the required shape:

    • i==n ⇒ is used to print the base of the triangle.
    • i+j==n+1 ⇒ is used to print the left side of the triangle.
    • j-i==n-1 ⇒ is used to print the right side of the triangle.
  • In line 22, we use the print() function to move on to the next line.



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