Lists are the most frequently used data structures of python. When we want to add more elements to a list, the extension of list happens. This can be done in following 5 different ways.
Using the Plus operator
Here we simply add the elements of a new list using the + operator. The behavior is similar to how we modify the values of a variable.
Examples
list = ['Mon','Tue','Wed'] list = list + ['Thu','Fri'] print(list)
Output
Running the above code gives us the following result −
['Mon', 'Tue', 'Wed', 'Thu', 'Fri']
Using Slicing
We can use slicing to add elements at the end of a list. Here we take the len() function to estimate the length of the list then slice it from the end and assign values from a new list.
Examples
list = ['Mon','Tue','Wed'] list[len(list):] = ['Thu','Fri'] print(list)
Output
Running the above code gives us the following result −
['Mon', 'Tue', 'Wed', 'Thu', 'Fri']
Using append()
We can append elements at the end of the list using appen() function. We can append one element at a time or we can append another list which remains as a list even after appending.
Examples
list = ['Mon','Tue','Wed'] list.append('Thu') list.append('Fri') list.append(['sat','sun']) print(list)
Output
Running the above code gives us the following result −
['Mon', 'Tue', 'Wed', 'Thu', 'Fri', ['sat', 'sun']]
Using Extend
extend() is a similar function to append where elements are added to a list. But unlike append(), we can add another list and the new elements added do not appear as a list inside a list.
Examples
list1 = ['Mon','Tue','Wed'] list2 = ['Thu','Fri','Sat'] list1.extend(list2) print(list1)
Output
Running the above code gives us the following result −
['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat']
Using chain()
We can use the chain() from the library itertools which concatenates multiple lists together. Here we can have more than two lists getting concatenated and finally all elements belong to one final list.
Examples
from itertools import chain list1 = ['Mon','Tue','Wed'] list2 = ['Thu','Fri'] list3 = ['Sat','Sun'] list4 = (list(chain(list1, list2,list3))) print(list4)
Output
Running the above code gives us the following result −
['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun']