def when(predicate, when_true):
  return lambda x: when_true(x) if predicate(x) else x

double_even_numbers = when(lambda x: x % 2 == 0, lambda x : x * 2)
print(double_even_numbers(2)) # 4
print(double_even_numbers(1)) # 1

class Rectangle:
    pass

class Square(Rectangle):
    pass

rectangle = Rectangle()
square = Square()

print(isinstance(rectangle, Rectangle))  # True
print(isinstance(square, Rectangle))     # True
print(isinstance(square, Square))        # True
print(isinstance(rectangle, Square))     # False

# Function to check Armstrong number
def is_armstrong_number(number):
    # Convert number to string to iterate over its digits
    num_str = str(number)
    
    # Calculate the sum of the cubes of each digit
    digit_sum = sum(int(digit) ** len(num_str) for digit in num_str)
    
    # Compare the sum with the original number
    if digit_sum == number:
        return True
    else:
        return False

# Prompt user for a number
number = int(input("Enter a number: "))

# Check if the number is an Armstrong number
if is_armstrong_number(number):
    print(number, "is an Armstrong number.")
else:
    print(number, "is not an Armstrong number.")

import re
_proposal_regex = r'(?:(?:(IKE|ESP):)?[\w/]+(?:/NO_EXT_SEQ)?(?:, ?(IKE|ESP):[\w/]+(?:/NO_EXT_SEQ)?)*)?'
_proposals_re = rf'(?P<proposals>{_proposal_regex}|)'
pattern = rf'received proposals: {_proposals_re}'
match = re.match(pattern, 'received proposals: ')
print(match.group('proposals') if match else "No match")  # Prints "No match"

# Python program to reverse a linked list
# Time Complexity : O(n)
# Space Complexity : O(n) as 'next'
#variable is getting created in each loop.

# Node class


class Node:

	# Constructor to initialize the node object
	def __init__(self, data):
		self.data = data
		self.next = None


class LinkedList:

	# Function to initialize head
	def __init__(self):
		self.head = None

	# Function to reverse the linked list
	def reverse(self):
		prev = None
		current = self.head
		while(current is not None):
			next = current.next
			current.next = prev
			prev = current
			current = next
		self.head = prev

	# Function to insert a new node at the beginning
	def push(self, new_data):
		new_node = Node(new_data)
		new_node.next = self.head
		self.head = new_node

	# Utility function to print the linked LinkedList
	def printList(self):
		temp = self.head
		while(temp):
			print temp.data,
			temp = temp.next


# Driver program to test above functions
llist = LinkedList()
llist.push(20)
llist.push(4)
llist.push(15)
llist.push(85)

print "Given Linked List"
llist.printList()
llist.reverse()
print "\nReversed Linked List"
llist.printList()

# Python program for implementation of Radix Sort
	
# A function to do counting sort of arr[] according to
# the digit represented by exp.
def countingSort(arr, exp1):
	
	n = len(arr)
	
	# The output array elements that will have sorted arr
	output = [0] * (n)
	
	# initialize count array as 0
	count = [0] * (10)
	
	# Store count of occurrences in count[]
	for i in range(0, n):
		index = (arr[i]/exp1)
		count[int((index)%10)] += 1
	
	# Change count[i] so that count[i] now contains actual
	# position of this digit in output array
	for i in range(1,10):
		count[i] += count[i-1]
	
	# Build the output array
	i = n-1
	while i>=0:
		index = (arr[i]/exp1)
		output[ count[ int((index)%10) ] - 1] = arr[i]
		count[int((index)%10)] -= 1
		i -= 1
	
	# Copying the output array to arr[],
	# so that arr now contains sorted numbers
	i = 0
	for i in range(0,len(arr)):
		arr[i] = output[i]

# Method to do Radix Sort
def radixSort(arr):

	# Find the maximum number to know number of digits
	max1 = max(arr)

	# Do counting sort for every digit. Note that instead
	# of passing digit number, exp is passed. exp is 10^i
	# where i is current digit number
	exp = 1
	while max1/exp > 0:
		countingSort(arr,exp)
		exp *= 10

# Driver code to test above
arr = [ 170, 45, 75, 90, 802, 24, 2, 66]
radixSort(arr)

for i in range(len(arr)):
	print(arr[i]),