如何在Python中最佳地将多维列表转换为单个项目列表? [英] How to optimally turn a multidimentional list into a single list of items in Python?

问题描述

可能的重复项:
从以下列表中的列表中删除一个列表Python
用Python整理的(不规则的)列表列表

Possible Duplicates:
Making a flat list out of list of lists in Python
Flatten (an irregular) list of lists in Python

输入一个列表，例如:[1,2，[3,4，[5,6,7，[8]]]，[9]，10]

Input a list such as: [1,2,[3,4,[5,6,7,[8]]],[9],10]

所需的输出:[1,2,3,4,5,6,7,8,9,10]

Desired output: [1,2,3,4,5,6,7,8,9,10]

当前，我具有以下递归函数:

Currently I have the following recursive function:

def fix_list( li , l = [] ):
    for i in li:
        try:
            len( i )
            fix_list( i, l )
        except:
            l.append( i )
    return l

我觉得try/except捕获有点花哨和缓慢，我想知道是否有更好/更优化的方法来执行此任务.非常感谢所有输入.

I feel like the try/except catch is a little gimmicky and slow, and I'm wondering if there is a better/more optimized way to perform this task. All input is greatly appreciated.

推荐答案

这里是一个迭代版本(最初是由Artsiom Rudzenka启发的)，它使用切片分配在适当的位置修改了列表，而不是在每次通过时都创建一个新列表.有趣的是，只需要遍历该列表！我对enumerate()的使用有点不合常规.我用它来跟踪列表中的索引，该索引在迭代时可能会不断增长，但实际上并没有使用实际的列表项.

Here is an iterative version (originally inspired by Artsiom Rudzenka's) that modifies the list in place using slice assignment rather than creating a new list on each pass. Interestingly, only one pass through the list is needed! My use of enumerate() is a little unorthodox; I use it to keep track of an index into a list that may be growing as I iterate over it, but don't actually use the actual list item.

def flattened(items, seqtypes=(list, tuple)):

    items = items[:]  # we will return a copy; remove to mutate original
    for i, _ in enumerate(items):
        while isinstance(items[i], seqtypes):
            items[i:i+1] = items[i]
    return items

print flattened([1,2,[3,4,[5,6,7,[8]]],[9],10])

发电机版本:

def flattener(items, seqtypes=(list, tuple)):

    items = items[:]
    for i, _ in enumerate(items):
        while isinstance(items[i], seqtypes):
            items[i:i+1] = items[i]
        yield items[i]

print list(flattener([1,2,[3,4,[5,6,7,[8]]],[9],10]))

这里是具有flatten()方法的list子类.像sort()和reverse()方法一样，这会使列表变异并返回None.

Here is a list subclass that has a flatten() method. Like the sort() and reverse() methods, this mutates the list and returns None.

class listy(list):

    def flatten(self, seqtypes=(list, tuple)):
        for i, _ in enumerate(self):
            while isinstance(self[i], seqtypes):
                self[i:i+1] = self[i]

lst = listy([1,2,[3,4,[5,6,7,[8]]],[9],10])
lst.flatten()
print lst

我从原始版本中大大简化了此操作.但是，我看到问题已经解决.

I simplified this pretty significantly from my original version. However, I see the question has been closed.

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