Python List extend()

 numbers1 = [3, 4, 5] numbers2 = [10, 20] # add the items of numbers1 to the number2 list numbers2.extend(numbers1) print(f"numbers1 = {numbers1}") print(f"numbers2 = {numbers2}")

numbers1 = [3, 4, 5] numbers2 = [10, 20, 3, 4, 5]

Syntax of List extend()

 list1.extend(iterable)

The extend() method takes a single argument.

• iterable - such as list, tuple, string, or dictionary

The extend() doesn't return anything; it modifies the original list.

Example 1: Using extend() Method

 languages = ['French', 'English'] languages1 = ['Spanish', 'Portuguese'] # append items of language1 to language languages.extend(languages1) print('Languages List:', languages)

Output

 Languages List: ['French', 'English', 'Spanish', 'Portuguese']

Example 2: Add Items from Other Iterables

 languages = ['French'] languages_tuple = ('Spanish', 'Portuguese') # add items of the tuple to the languages list languages.extend(languages_tuple) print( languages) languages_set = {'Chinese', 'Japanese'} # add items of the set to the languages list languages.extend(languages_set) print(languages)

Output

 ['French', 'Spanish', 'Portuguese'] ['French', 'Spanish', 'Portuguese', 'Japanese', 'Chinese']

Using + to Extend a List

We can also extend a list using the + operator..

 a = [1, 2] b = [3, 4] a = a + b print( a) # [1, 2, 3, 4]

Python extend() Vs append()

If you need to add the item itself (rather than its elements), use the append() method.

 a1 = [1, 2] a2 = [1, 2] b = (3, 4) # add items of b to the a1 list a1.extend(b) # [1, 2, 3, 4] print(a1) # add b itself to the a1 list a2.append(b) print(a2)

To learn more, visit list append() method.

Also Read:

• Python List insert()
• Python Program to Concatenate Two Lists