Python中识别不同子列表的首次与末次出现位置问题

我有一个包含多个子列表的列表J1，需要识别所有不同的子列表及其首次和末次出现的位置。以下是我的实现代码、当前输出以及期望输出：

原代码 #

J1 = [[0, 3, 7, 9, 10], [0, 3, 7, 9, 10], [0, 3, 7, 9, 10], [0, 0, 7, 9, 10], [0, 0, 7, 9, 10], [0, 0, 0, 9, 10]]

distinct_sublists = []
sublist_indices = {} 
for i, sublist in enumerate(J1):
 if sublist not in distinct_sublists:
     distinct_sublists.append(sublist)
     sublist_indices[tuple(sublist)] = [i, i]
else:
    sublist_indices[tuple(sublist)][1] = i

num_distinct_sublists = len(distinct_sublists)

first_last_locations = [[indices[0], indices[1]] for indices in sublist_indices.values()]

print("Number of distinct sublists in J1:", num_distinct_sublists)
print("First and last locations of distinct sublists in J1:", first_last_locations)
print("Distinct sublists", distinct_sublists)

当前输出 #

Number of distinct sublists in J1: 3
First and last locations of distinct sublists in J1: [[0, 0], [3, 3], [5, 5]]
Distinct sublists [[0, 3, 7, 9, 10], [0, 0, 7, 9, 10], [0, 0, 0, 9, 10]]

期望输出 #

Number of distinct sublists in J1: 3
First and last locations of distinct sublists in J1: [[0, 2], [3, 4], [5, 5]]
Distinct sublists [[0, 3, 7, 9, 10], [0, 0, 7, 9, 10], [0, 0, 0, 9, 10]]

错误原因 #

代码缩进错误：else块的缩进与for循环对齐，导致它属于for循环的else分支（仅在循环正常结束时执行一次），而非if判断的else分支（应该在子列表已存在时执行）。这就使得重复子列表出现时，无法更新对应的末次位置。

修正后的代码 #

只需调整else的缩进，使其与if对齐：

J1 = [[0, 3, 7, 9, 10], [0, 3, 7, 9, 10], [0, 3, 7, 9, 10], [0, 0, 7, 9, 10], [0, 0, 7, 9, 10], [0, 0, 0, 9, 10]]

distinct_sublists = []
sublist_indices = {} 
for i, sublist in enumerate(J1):
    if sublist not in distinct_sublists:
        distinct_sublists.append(sublist)
        sublist_indices[tuple(sublist)] = [i, i]
    else:
        sublist_indices[tuple(sublist)][1] = i

num_distinct_sublists = len(distinct_sublists)

first_last_locations = [[indices[0], indices[1]] for indices in sublist_indices.values()]

print("Number of distinct sublists in J1:", num_distinct_sublists)
print("First and last locations of distinct sublists in J1:", first_last_locations)
print("Distinct sublists", distinct_sublists)

修正后输出 #

Number of distinct sublists in J1: 3
First and last locations of distinct sublists in J1: [[0, 2], [3, 4], [5, 5]]
Distinct sublists [[0, 3, 7, 9, 10], [0, 0, 7, 9, 10], [0, 0, 0, 9, 10]]

内容的提问来源于stack exchange，提问作者aamirmodi123