🐍 Python Pattern Challenge — Day 12

Pattern printing is a great way to improve your Python logic, nested loops, mathematical thinking, and problem-solving skills. For Day 12, let's move beyond simple star patterns and create a number pattern based on Pascal's Triangle.

The challenge is to generate each row dynamically, where every number is calculated from the values of the previous row.

Today's Challenge

Write a Python program to print:

Best and cleanest code will be rewarded! 🏆

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Solution 1 — Using Nested for Loops

n = 6

for i in range(n):
    num = 1

    print("  " * (n - i - 1), end="")

    for j in range(i + 1):
        print(num, end="   ")
        num = num * (i - j) // (j + 1)

    print()

How it works:

The variable num starts with:

num = 1

For every next value, we calculate:

num = num * (i - j) // (j + 1)

This formula generates the next value of the current Pascal's Triangle row.

For example:

1
1 1
1 2 1
1 3 3 1
1 4 6 4 1

The spacing:

" " * (n - i - 1)

keeps the triangle centered.

Solution 2 — Using Lists

n = 6
row = [1]

for i in range(n):
    print("  " * (n - i - 1), end="")
    print(*row)

    row = [
        row[j] + row[j + 1]
        for j in range(len(row) - 1)
    ]

    row = [1] + row + [1]

How it works:

We start with:

row = [1]

Then every new row is created by adding neighboring values from the previous row.

For example:

1 3 3 1

produces:

1 4 6 4 1

because:

1 + 3 = 4 

3 + 3 = 6 

3 + 1 = 4

Then 1 is added to both ends.

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Solution 3 — Using a Function

def pascal(n):
    row = [1]

    for i in range(n):
        print("  " * (n - i - 1), end="")
        print(*row)

        row = [1] + [
            row[j] + row[j + 1]
            for j in range(len(row) - 1)
        ] + [1]


pascal(6)

How it works:

Putting the pattern inside a function makes it reusable.

You can easily change:

pascal(6)

to:

pascal(10)

to generate more rows.

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⚡ Short & Clean Code

r = [1]

for i in range(6):
    print("  " * (5-i), *r)
    r = [1] + [r[j] + r[j+1] for j in range(i)] + [1]

🔥 This compact version generates the same Pascal's Triangle pattern using a single main loop.

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🚀 Challenge Yourself

Can you modify this pattern:

• Generate 10 or 15 rows?
• Create Pascal's Triangle using only nested loops?
• Take the number of rows using input()?
• Print the triangle upside down?
• Replace the numbers with *?
• Calculate the sum of every row?
• Find the largest number in the generated triangle?

Drop your solution below! 👇

12 Days. 12 Patterns. Stronger Python Logic. 🐍🔥

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