Create a list of 2 variables

Question

If I have variables x and y , such that:

• x always a string
• y can be either a string or a list of strings

How to create a list z == [x, <all elements of y>] ?

For instance:

 x = 'x' y = 'y' # create z assert z == ['x', 'y'] 

 x = 'x' y = ['y', 'y2'] # create z assert z == ['x', 'y', 'y2'] 

Answer 1

 z = [x] + (y if isinstance(y, list) else [y]) 

Actually, I would avoid having y , which can be either a string or a list, but: this seems unnecessary.

Answer 2

 z = [x] if isinstance(y, list): z.extend(y) else: z.append(y) 

Answer 3

 import itertools z = itertools.chain(x, y)