How do I merge lists in python?

By using the + operator, like this:

>>> [1, 2] + [3, 4]
[1, 2, 3, 4]

+ operator can be used to merge two lists.

data1 = [1, 2, 3]
data2 = [4, 5, 6]

data = data1 + data2

print(data)

# output : [1, 2, 3, 4, 5, 6]

Lists can be merged like this in python.

Building on the same idea, if you want to join multiple lists or a list of lists to a single list, you can still use "+" but inside a reduce method like this,

from functools import reduce 

l1 = [1, 2, 3]
l2 = [4, 5, 6]
l3 = [7, 8, 9]
l4 = [10, 11, 12]

l = [l1, l2, l3, l4]

data = reduce(lambda a, b: a+b, l)
print(data)

# output : [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]