Check if an URL is valid or not using Regular Expression

import re

def isValidURL(str):

regex = ("((http|https)://)(www.)?" +

"[a-zA-Z0-9@:%._\\+~#?&//=]" +

"{2,256}\\.[a-z]" +

"{2,6}\\b([-a-zA-Z0-9@:%" +

"._\\+~#?&//=]*)")

p = re.compile(regex)

if (str == None):

return False

if(re.search(p, str)):

return True

else:

return False

url = "https://www.pythonforengineers.in"

if(isValidURL(url) == True):

print("Yes")

else:

print("No")

Program to print double sided stair-case pattern

def pattern(n):

for i in range(1,n+1):

k =i + 1 if(i % 2 != 0) else i

for g in range(k,n):

if g>=k:

print(end=" ")

for j in range(0,k):

if j == k - 1:

print(" * ")

else:

print(" * ", end = " ")

n = 10

pattern(n)