Python：如何同时向列表中添加两个列表？

Question

Let's say I have a list

l1 = []

another list

l2 = ['a','b']

and two variables

u = 1
z = 2

Now I would like to add l2 to l1 and the two variables as a list to l1 as well. One can do it in two steps using append:

l1.append(l2)
l1.append(list((u,z)))

which gives me the desired output

[['a', 'b'], [1, 0]]

But something like

l1.append(l2, list((u,z)))

does not work. Is there a way to get the same output I obtain for the two steps in a nice oneliner ie can one simultaneously append a list by two lists?

Answer 1

l1.extend([l2, [u,z]])

append can only add one element to a list. extend takes a list and adds all the elements in it to other list.

Answer 2

You can use extend as follows:

l1.extend([l2,[u,z]])

Or just:

l1 + [l2] + [[u,z]]

Answer 3

You can use any of the following methods:

Method 1 :

>>> l1.extend([l2, [u,z]])
>>> l1
[['a', 'b'], [1, 2]]

append : Appends object at end
extend : Extends list by appending elements from the iterable

Method 2 :

>>> l1 += [l2] + [[u, z]]
>>> l1
[['a', 'b'], [1, 2]]

Answer 4

通过创建生成器很简单

import itertools
for item in itertools.chain(listone, listtwo):
# do what you want to do with this merged list