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
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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).