將3D列表更改為2D列表

Question

我想將3D列表（list_1）轉換為2D列表（list_2）。 例如：

list_1: [[[3], [4]], [[5], [6]], [[7], [8]]]
list_2: [[3, 4], [5, 6], [7, 8]]

這是我已經嘗試過的：

[e for sl in lst for e in sl]

但是結果會有所不同：

[[3], [4], [5], [6], [7], [8]]

Answer 1

出於可讀性考慮，我建議使用itertools.chain將此處的內部列表展平：

from itertools import chain
l = [[[3], [4]], [[5], [6]], [[7], [8]]]

[list(chain.from_iterable(i)) for i in l]
# [[3, 4], [5, 6], [7, 8]]

---

按照您的方法，您需要進行額外的循環以平化內部列表：

[[i for e in sl for i in e] for sl in l]
# [[3, 4], [5, 6], [7, 8]]

Answer 2

另外一個選項：

[reduce(list.__add__, x)  for x in list_1]

Answer 3

您也可以這樣：

l = [[[3], [4]], [[5], [6]], [[7], [8]]]

print ([sum(item, []) for item in l])

輸出：

[[3, 4], [5, 6], [7, 8]]

Answer 4

您接近：

[[c for b in a for c in b] for a in lst]

Answer 5

如果所有嵌套列表都包含單個元素，則可以使用拆包：

d = [[[3], [4]], [[5], [6]], [[7], [8]]]
new_d = [[i for [i] in b] for b in d]

輸出：

[[3, 4], [5, 6], [7, 8]]