# Basic syntax:
first_list.append(second_list) # Append adds the second_list as an
#	element to the first_list
first_list.extend(second_list) # Extend combines the elements of the
#	first_list and the second_list
# Note, both append and extend modify the first_list in place
# Example usage for append:
first_list = [1, 2, 3, 4, 5]
second_list = [6, 7, 8, 9]
first_list.append(second_list)
print(first_list)
--> [1, 2, 3, 4, 5, [6, 7, 8, 9]]
# Example usage for extend:
first_list = [1, 2, 3, 4, 5]
second_list = [6, 7, 8, 9]
first_list.extend(second_list)
print(first_list)
--> [1, 2, 3, 4, 5, 6, 7, 8, 9]

#adding two or more elements in a list
list1 = [1,2,3,4,5]
list1.extend([6,7,8])
print(list1)
#output = [1, 2, 3 ,4 ,5, 6, 7, 8]

# Way 1
list1 + list2
# Way 2
list1.extend(list2)
# Way 3
list1.append(list2[:])
# Way 4
list1.append(*list2)

# testing
a = [1, 2]
b = [3, 4]
a.extend(b)
print(a) # [1, 2, 3, 4]

Difference between List append() and List extend() method
a =[1,2]
b= [3,4]
# append() method
a.append(b)
print("Using append() method", a)
x =[1,2]
y= [3,4]
# extend() method
x.extend(y)
print("Using extend() method", x)

animals = ['dog', 'cat']
# tuple
mammals = ('tiger', 'elephant')
animals.extend(mammals)
print('Updated list:', animals)
# dictionary
birds = {'owl': 1, 'parrot': 2}
animals.extend(birds)
print('Updated list:', animals)
#Updated list: ['dog', 'cat', 'tiger', 'elephant']
#Updated list: ['dog', 'cat', 'tiger', 'elephant', 'owl', 'parrot']

# My List
my_list = ['geeks', 'for', 'geeks']
  
# My Tuple
my_tuple = ('DSA', 'Java')
  
# My Set
my_set = {'Flutter', 'Android'}
  
# Append tuple to the list
my_list.extend(my_tuple)
  
print(my_list)
  
# Append set to the list
my_list.extend(my_set)
  
print(my_list)
['geeks', 'for', 'geeks', 'DSA', 'Java']
['geeks', 'for', 'geeks', 'DSA', 'Java', 'Android', 'Flutter']

Python Program to extend the list
# Programming list
programming_list = ['C','C#','Python','Java']
frontend_programming =['CSS','HTML','JavaScript']
# add the frontend_progamming list into the existing list
programming_list.extend(frontend_programming)
# Note that iterable element is added to the end of the list
print('The new extended list is :', programming_list)