查看tensor的形状，行列大小

torch.size是tuple（元组的子类，因此他支持元组所有的操作，如x.size()[0]

import pandas as pd
import numpy as np

import torch

x = torch.rand(5,3)
print(x.size())
print(x.size()[0])
print(x.size()[1])

torch.Size([5, 3])
5
3