Append multiple lists Python

Using the + operator or zip function or itertools chain you can append multiple lists in Python. The + operator does a straightforward job of joining the lists together.

Append multiple lists of Python

Simple example code appends elements of 2-3 lists to one list.

l1 = [1, 3, 5, 5, 4]
l2 = [4, 6, 2, 8, 10]
l3 = [7, 5, 2, 9, 11]

# Using + operator
res1 = l1 + l2 + l3
print(res1)

# Using itertools.chain()
from itertools import chain

res2 = list(chain(l1, l2, l3))
print(res2)

# With zip
res_list = list(zip(l1, l2, l3))
print(res_list)

Output:

Is it possible to append multiple lists at once?

Answer: yes this is possible using the extend function.

x.extend(y+z)

or

x += y+z

or even

x = x+y+z

If you prefer a slightly more functional approach, you could try:

import functools as f

x = [1, 2, 3]
y = [4, 5, 6]
z = [7, 8, 9]

x = f.reduce(lambda x, y: x+y, [y, z], x)

Remember that using extend() modifies the list in-place, while the + operator creates a new list. Choose the method that best fits your requirements. If you want to keep the original lists unchanged, use the + operator and assign the result to a new variable.

Comment if you have any doubts or suggestions on this Python list topic.

Note: IDE: PyCharm 2021.3.3 (Community Edition)

Windows 10

Python 3.10.1

All Python Examples are in Python 3, so Maybe its different from python 2 or upgraded versions.