Question

我有一个包含整数的列表的python列表，我需要将它转换为单个列表。

如果列表中没有包含任何整数（只有其他列表），我可以使用此处提供的解决方案：Making a flat list out of list of lists in Python

即，

[item for sublist in main_list for item in sublist]

例如，

test_list = [[1,2,3,4,5,6], [7,8,9,10], [11,12,13,14]]
test_list = [item for sublist in test_list for item in sublist]
[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14]

但是，如果列表中包含整数，则此解决方案不起作用：

test_list_2 = [[1,2,3,4,5,6], 0, [7,8,9,10], [11,12,13,14]]
test_list_2 = [item for sublist in test_list_2 for item in sublist]

Traceback (most recent call last):

File "<ipython-input-28-c6531e09f706>", line 1, in <module>
test_list_2 = [item for sublist in test_list_2 for item in sublist]

TypeError: 'int' object is not iterable

有没有办法规避这个问题？感谢。

Answer 1

你需要做这样的事情：

>>> test_list_2 = [[1,2,3,4,5,6], 0, [7,8,9,10], [11,12,13,14]]
>>> def lift_int(v):
...     if not isinstance(v, list): 
...         return [v]
...     else:
...         return v
... 
>>> test_list_2 = [item for sublist in test_list_2 for item in lift_int(sublist)]
>>> test_list_2
[1, 2, 3, 4, 5, 6, 0, 7, 8, 9, 10, 11, 12, 13, 14]

Answer 2

由于您试图压缩列表，我认为最好的方法是使用generator function。请注意，这会递归地压缩您的列表而不仅仅是一个级别。

>>> def flatten(items):
...     for item in items:
...         if isinstance(item, list):
...             yield from flatten(item)
...         else:
...             yield item
... 
>>> list(flatten(test_list_2))
[1, 2, 3, 4, 5, 6, 0, 7, 8, 9, 10, 11, 12, 13, 14]

Answer 3

如果你想继续列表（in）理解，你可以这样做：

test_list = [[1,2,3,4,5,6], 0, [7,8,9,10], [11,12,13,14]]
print [item for sublist in test_list for item in (sublist if isinstance(sublist, list) else [sublist])]

test_list = [[1,2,3,4,5,6], 0, [7,8,9,10], 1, 2, 3, [11,12,13,14], 1234]
print [item for sublist in test_list for item in (sublist if isinstance(sublist, list) else [sublist])]

让它更难理解。

Answer 4

你也可以尝试这个

def convert_to_list(num):
    return [num] if not isinstance(num, list) else num

然后使用itertools

>>>import itertools
itertools.chain(*map(convert_to_list, test_list_2))
<itertools.chain at 0x7ff211650550>
>>>list(itertools.chain(*map(convert_to_list, test_list_2)))
[1, 2, 3, 4, 5, 6, 0, 7, 8, 9, 10, 11, 12, 13, 14]

Answer 5

def convert(data):
    result = []
    for sublist in test_list_2:
        if type(sublist) is list:
            result += sublist
        else:
            result.append(sublist)
    return result

convert函数将列表和整数列表转换为列表

Answer 6

你也可以简单地使用：

test_list = reduce(lambda x, y: x + (y if isinstance(y, list) else [y]), test_list)

列表和整数列表

6 个答案: