Possible to append multiple lists at once? (Python)

Question

I have a bunch of lists I want to append to a single list that is sort of the "main" list in a program I'm trying to write. Is there a way to do this in one line of code rather than like 10? I'm a beginner so I have no idea...

For a better picture of my question, what if I had these lists:

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

And want to append y and z to x. Instead of doing:

x.append(y) x.append(z) 

Is there a way to do this in one line of code? I already tried:

x.append(y, z) 

And it wont work.

Answer 1

x.extend(y+z) 

should do what you want

or

x += y+z 

or even

x = x+y+z 

Answer 2

You can use sum function with start value (empty list) indicated:

a = sum([x, y, z], []) 

This is especially more suitable if you want to append an arbitrary number of lists.