Python Program to Concatenate Two Lists

In this example, you will learn to concatenate two lists in Python.

To understand this example, you should have the knowledge of the following Python programming topics:

• Python List
• Python List extend()

1. Example 1: Using + operator

list_1 = [1, 'a']
list_2 = [3, 4, 5]

list_joined = list_1 + list_2
print(list_joined)

Output

[1, 'a', 3, 4, 5]

In this example, + operator is used to concatenate two lists.

2. Example 2: Using iterable unpacking operator *

list_1 = [1, 'a']
list_2 = range(2, 4)

list_joined = [*list_1, *list_2]
print(list_joined)

Output

[1, 'a', 2, 3]

* operator allows unpacking inside the list or tuple.

3. Example 3: With unique values

list_1 = [1, 'a']
list_2 = [1, 2, 3]

list_joined = list(set(list_1 + list_2))
print(list_joined)

Output

[1, 2, 3, 'a']

If you want the unique items from a concatenated list, you can use list() and set(). set() selects the unique values and list() converts the set into list.

4. Example 4: Using extend()

list_1 = [1, 'a']
list_2 = [1, 2, 3]

list_2.extend(list_1)
print(list_2)

Output

[1, 2, 3, 1, 'a']

Using extend(), you can concatenate a list to another list as shown in example above.