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Python Exercise: Print out the first n rows of Pascal's triangle

Python Functions: Exercise-13 with Solution

Write a Python function that prints out the first n rows of Pascal's triangle.

Note : Pascal's triangle is an arithmetic and geometric figure first imagined by Blaise Pascal.

Sample Pascal's triangle :

Pascal's triangle

Each number is the two numbers above it added together

Sample Solution :-

Python Code :

def pascal_triangle(n):
   trow = [1]
   y = [0]
   for x in range(max(n,0)):
      print(trow)
      trow=[l+r for l,r in zip(trow+y, y+trow)]
   return n>=1
pascal_triangle(6) 

Sample Output:

[1]                                                                                                           
[1, 1]                                                                                                        
[1, 2, 1]                                                                                                     
[1, 3, 3, 1]                                                                                                  
[1, 4, 6, 4, 1]                                                                                               
[1, 5, 10, 10, 5, 1]  

Flowchart:

Flowchart: Python exercises: Print out the first n rows of Pascal's tringle.

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Python: Tips of the Day

Find current directory and file's directory:

To get the full path to the directory a Python file is contained in, write this in that file:

import os 
dir_path = os.path.dirname(os.path.realpath(__file__))

(Note that the incantation above won't work if you've already used os.chdir() to change your current working directory, since the value of the __file__ constant is relative to the current working directory and is not changed by an os.chdir() call.)

To get the current working directory use

import os
cwd = os.getcwd()

Documentation references for the modules, constants and functions used above:

  • The os and os.path modules.
  • The __file__ constant
  • os.path.realpath(path) (returns "the canonical path of the specified filename, eliminating any symbolic links encountered in the path")
  • os.path.dirname(path) (returns "the directory name of pathname path")
  • os.getcwd() (returns "a string representing the current working directory")
  • os.chdir(path) ("change the current working directory to path")

Ref: https://bit.ly/3fy0R6m