python - 如何在 python 中展平嵌套列表？

Question

如何转换:

THIS = \
['logging',
 ['logging', 'loggers',
  ['logging', 'loggers', 'MYAPP',
   ['logging', 'loggers', 'MYAPP', '-handlers'],
   ['logging', 'loggers', 'MYAPP', 'propagate']
  ]
 ],
 ['logging', 'version']
]

进入:

THAT = [
    ['logging'],
    ['logging', 'version'],
    ['logging', 'loggers'],
    ['logging', 'loggers', 'MYAPP'],
    ['logging', 'loggers', 'MYAPP', '-handlers'],
    ['logging', 'loggers', 'MYAPP', 'propagate']
]

在 python 中(它不需要排序，只是展平)？

我尝试了很多方法，但找不到解决方法。

Answer 1

用递归生成器解决

def flatten(items):
    non_list_items = []

    for item in items:
        if isinstance(item, list):
            for inner_item in flatten(item):
                yield inner_item
        else:
            non_list_items.append(item)

    yield non_list_items

根据您的输入进行测试:

from pprint import pprint

>>> pprint(sorted(flatten(THIS)))
[['logging'],
 ['logging', 'loggers'],
 ['logging', 'loggers', 'MYAPP'],
 ['logging', 'loggers', 'MYAPP', '-handlers'],
 ['logging', 'loggers', 'MYAPP', 'propagate'],
 ['logging', 'version']]