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📅  最后修改于: 2022-03-11 14:45:05.004000             🧑  作者: Mango
>>> l = [[1, 2, 3], [4, 5, 6], [7], [8, 9]] >>> sum(l, []) [1, 2, 3, 4, 5, 6, 7, 8, 9]