python中:: 和 // 怎么理解

x_2 = x_1[::len(loss_record['train']) // len(loss_record['dev'])]

// 代表整除

步进13

 

 

所以

x_2 = x_1[::len(loss_record['train']) // len(loss_record['dev'])]

等价于

 x_2 = x_1[::13]

等价于

range(0, 9035, 13)