我試圖從嵌套的元組串列中迭代以獲取第一個元素。我得到的只是零元組。我想要的是
###expected output
### [['d51', 'd874', 'd486','d329','d1328', 'd1268','d114','d792', 'd717','d522'],
###['d51, 'd874', 'd486','d329', 'd1328', 'd1268']]
tupple=[[('d51', 23), ('d874', 20), ('d486', 15), ('d329', 12), ('d1328', 11), ('d1268', 11), ('d114', 11), ('d792', 10), ('d717', 10),('d522', 10)],
[('d51', 23), ('d874', 20), ('d486', 15), ('d329', 12), ('d1328', 11), ('d1268', 11)]]
new=[]
slow=[i[0] for i in tupple]
for item in tupple:
new.append(item[0][:])
new
##output [('d51', 23), ('d51', 23)]
uj5u.com熱心網友回復：
您可以像這樣使用串列推導：
new = [[item[0] for item in inner] for inner in tupple]
# [['d51', 'd874', 'd486', 'd329', 'd1328', 'd1268', 'd114', 'd792', 'd717', 'd522'], ['d51', 'd874', 'd486', 'd329', 'd1328', 'd1268']]
uj5u.com熱心網友回復：
您可以使用內置zip()解包來獲取每個內部串列的第一個元素。
data = ...
output = [next(zip(*items)) for items in data]
uj5u.com熱心網友回復：
對于任意深度嵌套的元組*：
from typing import Union, Tuple, List
NestedTuple = Union[List["NestedTuple"], Tuple[str, int]]
UnpackedNestedTuple = Union[List["UnpackedNestedTuple"], List[str]]
def extract_first_element(nested_tuples: List[NestedTuple]) -> UnpackedNestedTuple:
return [el[0] if isinstance(el, tuple) else extract_first_element(el) for el in nested_tuples]
# #####################################
# TESTING
# #####################################
tupple = [ [ ("d51", 23), ("d874", 20), ("d486", 15), ("d329", 12), ("d1328", 11), ("d1268", 11), ("d114", 11), ("d792", 10), ("d717", 10), ("d522", 10), ], [ ("d51", 23), ("d874", 20), ("d486", 15), ("d329", 12), ("d1328", 11), ("d1268", 11), ], ]
assert extract_first_element(tupple) == [
["d51", "d874", "d486", "d329", "d1328", "d1268", "d114", "d792", "d717", "d522"],
["d51", "d874", "d486", "d329", "d1328", "d1268"],
]
# XXX: recursion depth can become an issue
recur_error_ex = tupple
for _ in range(100000):
recur_error_ex = [recur_error_ex]
try:
extract_first_element(recur_error_ex) # RecursionError: maximum recursion depth exceeded
except RecursionError as e:
print(f"WARNING: {e}")
* 達到最大遞回深度。查看示例
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標籤：Python python-3.x 列表 循环 元组