二维表为一

Question

我有多个维度列表输出，我想把它变成一个维度。

   a = [1,0,3,0,5,0]

   new_list = []

   l = [2,4,6]



   for i in a:
     new_list.append(l)



    print(new_list)

    #[[2, 4, 6], [2, 4, 6], [2, 4, 6], [2, 4, 6], [2, 4, 6], [2, 4, 6]]

Answer 1

使用list-comprehension

s = [[2, 4, 6], [2, 4, 6], [2, 4, 6], [2, 4, 6], [2, 4, 6], [2, 4, 6]]

print([x for subl in s for x in subl])

输出：

[2, 4, 6, 2, 4, 6, 2, 4, 6, 2, 4, 6, 2, 4, 6, 2, 4, 6]

Answer 2

如果你想要一个平面列表，你真的应该extend这个列表，而不是append。但是如果你已经有了它，最快最安全的方法就是使用itertools：

list(itertools.chain.from_iterable(your_list))

Answer 3

您可以递归地执行此操作：

def flatten(s):
    if s == []:
        return s
    if isinstance(s[0], list):
        return flatten(s[0]) + flatten(s[1:])
    return s[:1] + flatten(s[1:])

l = [[2, 4, 6], [2, 4, 6], [2, 4, 6], [2, 4, 6], [2, 4, 6], [2, 4, 6]]
res = flatten(l)
print(res) # prints [2, 4, 6, 2, 4, 6, 2, 4, 6, 2, 4, 6, 2, 4, 6, 2, 4, 6]