Python中将嵌套列表扁平化的多种实现方法

xss = [[1, 2, 3], [4, 5, 6], [7], [8, 9]]
flat_list = [x for xs in xss for x in xs]
print(flat_list)

import itertools
list2d = [[1, 2, 3], [4, 5, 6], [7], [8, 9]]
# 使用 chain()
merged1 = list(itertools.chain(*list2d))
# 使用 chain.from_iterable()
merged2 = list(itertools.chain.from_iterable(list2d))
print(merged1)
print(merged2)

xss = [[1, 2, 3], [4, 5, 6], [7], [8, 9]]
flat_list = sum(xss, [])
print(flat_list)

from functools import reduce
import operator
xss = [[1, 2, 3], [4, 5, 6], [7], [8, 9]]
# 使用 operator.concat
out1 = reduce(operator.concat, xss)
# 使用 operator.iconcat
out2 = reduce(operator.iconcat, xss, [])
print(out1)
print(out2)

from typing import Iterable

def flatten(items):
    for x in items:
        if isinstance(x, Iterable) and not isinstance(x, (str, bytes)):
            yield from flatten(x)
        else:
            yield x

simple = [[1, 2, 3], [4, 5, 6], [7], [8, 9]]
flat_list = list(flatten(simple))
print(flat_list)

import itertools
from functools import reduce
import operator
from typing import Iterable

# 嵌套列表推导式
def nested_list_comprehension(xss):
    return [x for xs in xss for x in xs]

# itertools.chain.from_iterable()
def itertools_chain(xss):
    return list(itertools.chain.from_iterable(xss))

# sum()
def pythons_sum(xss):
    return sum(xss, [])

# functools.reduce() with operator.concat
def reduce_concat(xss):
    return reduce(operator.concat, xss)

# functools.reduce() with operator.iconcat
def reduce_iconcat(xss):
    return reduce(operator.iconcat, xss, [])

# 自定义递归函数
def custom_flatten(items):
    for x in items:
        if isinstance(x, Iterable) and not isinstance(x, (str, bytes)):
            yield from custom_flatten(x)
        else:
            yield x

xss = [[1, 2, 3], [4, 5, 6], [7], [8, 9]]
print(nested_list_comprehension(xss))
print(itertools_chain(xss))
print(pythons_sum(xss))
print(reduce_concat(xss))
print(reduce_iconcat(xss))
print(list(custom_flatten(xss)))

from typing import Iterable

def flatten(items):
    for x in items:
        if isinstance(x, Iterable) and not isinstance(x, (str, bytes)):
            yield from flatten(x)
        else:
            yield x

complicated = [[1, [2]], (3, 4, {5, 6}, 7), 8, "9"]
flat_list = list(flatten(complicated))
print(flat_list)