We can print a plethora of patterns using Python. The only prerequisite to do this is a good understanding of how loops work in Python.
Here, we will be using simple for loops to generate a left-angled triangle using numbers.
A triangle is said to be left-angled if – and only if – it has one angle equal to 90 degrees on its right side.
To execute this using Python programming, we will be using two for loops nested within an outer for loop:
Let’s look at the below code snippet.
# Number of rowsrows = 5# Iterating value for columnk = 2*rows-2# Loop through rowsfor i in range(rows):# Loop to print initial spacesfor j in range(k):print(end=" ")# Updating value of Kk = k-2# Loop to print the numbersfor j in range(i+1):print(j+1, end=" ")print()
In line 2, we take the input for the number of rows (i.e., length of the triangle).
In line 5, we create the iterating variable k, which will be used later to handle the number of columns.
From lines 8 to 20, we create the outer for loop to iterate through the number of rows.
In lines 11 and 12, we create the first inner nested loop to print the initial spaces.
In line 15, the value of k is updated so that the output is a left-angled triangle, i.e., the characters are printed from right to left. Unless it is updated, the triangle will be a right-angled triangle.
In line 18, we create our second inner nested loop to print the numbers.
In line 19, we printed j+1, which results in iteration from 1 (since j + 1) to the length of i in each row. As i keeps increasing with increasing rows, the numbers keep increasing as the line number increases.