在Python中对嵌套列表进行排序和分组

nested_list = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
sorted_list = sorted(nested_list, key=lambda x: x[0])
print(sorted_list)

from operator import itemgetter

nested_list = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
sorted_list = sorted(nested_list, key=itemgetter(0))
print(sorted_list)

from itertools import groupby

nested_list = [[1, 2, 3], [1, 5, 6], [2, 8, 9], [2, 5, 6]]
grouped_list = [(k, list(v)) for k, v in groupby(sorted(nested_list, key=lambda x: x[0]), lambda x: x[0])]
print(grouped_list)