Topic
1. Print Numbers 1–1002. Print Even Numbers in Range3. Print Odd Numbers in Range4. Sum of Digits5. Reverse Digits of a Number6. Calculate Factorial (Loop)7. Fibonacci Series8. Palindrome Number Check9. Count Digits in a Number10. GCD of Two Numbers (Loop)11. LCM of Two Numbers (Loop)12. Print Prime Numbers in Range13. Count Prime Numbers in Range14. Check Composite Number15. Power of 2 Checker16. Print Number Pattern17. Print Star Pattern18. Armstrong Numbers in Range19. Strong Numbers in Range20. Sum of Series 1/1 + 1/2 + … + 1/N21. Print Multiplication Series22. Print Pyramid Pattern23. Print Inverted Pyramid Pattern24. Print Floyd's Triangle25. Print Pascal's Triangle

Print Pascal's Triangle in Python

Print Pascal's triangle up to N rows using a loop and binomial coefficients.

IntermediateLoop ProgramsExample 25 of 25
print-pascal-s-triangle.py
1# Program to print Pascal's triangle
2

3rows = int(input("Enter number of rows: "))
4

5for n in range(rows):
6    # print leading spaces
7    print(" " * (rows - n), end="")
8    coef = 1
9    for k in range(n + 1):
10        print(coef, end=" ")
11        coef = coef * (n - k) // (k + 1)
12    print()

Output

Enter number of rows: 5
    1 
   1 1 
  1 2 1 
 1 3 3 1 
1 4 6 4 1

What's going on

We compute binomial coefficients iteratively in each row using the relation:

coef = coef * (n - k) // (k + 1).

After this program

If the idea is still fuzzy, read Day 9: Loops and Iteration in the Python course. For a short check, try the Python quiz (300 questions). Stay with all 25 loop programs, or see every topic on Python exercises.

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