Python Program to Print a Right Triangle Star Pattern

mediumNested loopsPython

Pattern programs are a practical-exam favourite. Python's string repetition makes this one very short.

The question

Read the number of rows n and print a right-angled triangle of stars: 1 star on the first row, 2 on the second, and so on. No spaces between the stars.

The code

program.py

n = int(input())
for i in range(1, n + 1):
    print("*" * i)

Try it Yourself »

Input

Output

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

How it works

1The loop runs once per row, i going from 1 to n.
2"*" * i repeats the star i times — 1 star on row 1, 2 on row 2, and so on.
3Each print() starts a new row.

Common mistakes

range(n) starts at 0, so the first row prints nothing.
Adding spaces between stars when the question asks for none.

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