在Python中将元组（'Id'，'row 1'），（'Id'，'row 2'）的集合转换为List ['Id'，['row 1'，'row2']

我将分两个步骤进行。首先，创建一个字典，其中键是元组的第一个元素，值是共享相同第一个元素的所有第二个元素的列表。

其次，将键和值插入适当的列表中。

import itertools

# your initial set of tuples
tuples = {('Id', 'row1'), ('Id', 'row2'), ('Id2', 'row3')}

# create a dict, as above - 
#    key is the first element of tuple
#    value is a list of the second elements of those tuples
dct = {}
for t in tuples:
    dct.setdefault(t[0], []).append(t[1])
print(dct)
# {'Id2': ['row3'], 'Id': ['row1', 'row2']}

# coalesce the dict's keys and values into a list
# we use itertools.chain to make this more straightforward,
# but it's essentially concatenating the tuple elements of dct.items() to
# each other, by using the unpacking operator `*` to provide them individually
# as arguments.
outp = list(itertools.chain(*dct.items()))
print(outp)
# ['Id2', ['row3'], 'Id', ['row1', 'row2']]

这具有线性时间复杂度，因为它tuples正好遍历输入（）的每个元素两次。