其结果将是一个新列表,由对表达式依据后面的 for 和 if 子句的内容进行求值计算而得出。...= [[1,2,3], [4,5,6], [7,8,9]]
>>> [num for elem in vec for num in elem]
[1, 2, 3, 4, 5, 6, 7, 8, 9]
列表推导式可以使用复杂的表达式和嵌套函数...import pi
>>> [str(round(pi, i)) for i in range(1, 6)]
['3.1', '3.14', '3.142', '3.1416', '3.14159']
嵌套的列表推导式...[9, 10, 11, 12],
... ]
下面的列表推导式将交换其行和列
>>> [[row[i] for row in matrix] for i in range(4)]
[[1, 5..., 9], [2, 6, 10], [3, 7, 11], [4, 8, 12]]
如上节所示,嵌套的列表推导式是基于跟随其后的 for 进行求值的,所以这个例子等价于:
>>> transposed