How to make a hollow inverted left-angled triangle with numbers

In this shot, we will discuss how to generate a hollow inverted left-angled triangle with numbers in Python. The main prerequisite for this is to have a good understanding of for loops.

Description

A triangle is said to be left-angled if it has an angle equal to 90 degrees on its right side. An inverted left-angled triangle is just the upside-down version of a left-angled triangle.

To create the pattern, we will use 2 for loops:

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

Code

Let’s look at the code snippet below.

# Number of rows
n = 5
# Loop through rows
for i in range(1, n+1):
    # Loop through columns
    for j in range(1, n+1):
        # Printing Pattern
        if (j == n) or (i == 1) or (i == j):
            print(i, end=" ")
        else:
            print(" ", end=" ")
    print()

Explanation

  • In line 2, we take the input for the number of rows (i.e., the length of the triangle). In this case, it is set to 5.

  • In line 5, we create a for loop to iterate through the number of rows.

  • In line 7, we create an inner nested for loop to iterate through the number of columns.

  • From lines 9 to 12, we use conditional statements to create the pattern, and check to see if the character should be printed at that position or if a space character should be added instead. The end statement helps to stay on the same line.

  • In line 13, we use the print() statement to move to the next line.

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