import torch
import numpy as np
# 1>>> 初始化tensor
# (1) 直接创建数值tensor
data = [[1, 2], [3, 4]]
x_data = torch.tensor(data)
# (2) 由Numpy数组转为tensor
np_array = np.array(data)
x_np = torch.from_numpy(np_array)
# (3) 来自其他tensor
x_rand = torch.rand_like(x_data, dtype=torch.float)
# (4) 创建随机tensor
shape = (2, 3, )
rand_tensor = torch.rand(shape)
ones_tensor = torch.ones(shape)
zeros_tensor = torch.zeros(shape)
# 2>>> tensor属性
tensor1 = torch.rand(3, 4)
print(f"形状:\n {tensor1.shape}")
print(f"数据类型:\n {tensor1.dtype}")
print(f"存放CPU或GPU:\n {tensor1.device}")
print(f"维度:\n {tensor1.ndim}")
print(f"数据:\n {tensor1.data}")
# 3>>> tensor切片
tensor2 = torch.rand(3, 4)
tensor2[..., -1] = 500
print(f"第一行:{tensor2[0]}")
print(f"第一行第一个:{tensor2[0][0]}")
print(f"第一列:{tensor2[:, 0]}")
print(f"最后一列: