*My post explains how to create and acceess a tensor.
dim() can get the number of dimensions from the 0D or more D tensor of zero or more elements as shown below:
*Memos:
import torch
my_tensor = torch.tensor(-3) # 0D tensor
my_tensor.dim() # 0
my_tensor = torch.tensor([-3, 7, -5, 2, 6, 3])
# 1D tensor
my_tensor.dim() # 1
my_tensor[0].dim() # 0
my_tensor = torch.tensor([[-3, 7, -5], [2, 6, 3], # 2D tensor
[8, 0, -1], [4, 9, -6]])
my_tensor.dim() # 2
my_tensor[0].dim() # 1
my_tensor[0][0].dim() # 0
my_tensor = torch.tensor([[[-3, 7], [-5, 2], [6, 3]], # 3D tensor
[[8, 0], [-1, 4], [9, -6]],
[[5, -2], [-7, 9], [1, 1]],
[[6, -4], [0, -9], [3, 5]]])
my_tensor.dim() # 3
my_tensor[0].dim() # 2
my_tensor[0][0].dim() # 1
my_tensor[0][0][0].ndim # 0
size() can get a size from the 0D or more D tensor of zero or more elements as shown below:
*Memos:
-
size()can be used with a tensor but not withtorch. - The 1st argument with a tensor is
dim(Optional-Type:int). -
shape is the alias of
dim().
import torch
my_tensor = torch.tensor(-3) # 0D tensor
my_tensor.size()
# torch.Size([])
my_tensor = torch.tensor([-3, 7, -5, 2, 6, 3]) # 1D tensor
my_tensor.size()
# torch.Size([6])
my_tensor.size(dim=0)
my_tensor.size(dim=-1)
# 6
my_tensor[0].size()
# torch.Size([])
my_tensor = torch.tensor([[-3, 7, -5], [2, 6, 3], # 2D tensor
[8, 0, -1], [4, 9, -6]])
my_tensor.size()
# torch.Size([4, 3])
my_tensor.size(dim=0)
my_tensor.size(dim=-2)
# 4
my_tensor.size(dim=1)
my_tensor.size(dim=-1)
my_tensor[0].size(dim=0)
my_tensor[0].size(dim=-1)
# 3
my_tensor[0].size()
# torch.Size([3])
my_tensor[0][0].size()
# torch.Size([])
my_tensor = torch.tensor([[[-3, 7], [-5, 2], [6, 3]], # 3D tensor
[[8, 0], [-1, 4], [9, -6]],
[[5, -2], [-7, 9], [1, 1]],
[[6, -4], [0, -9], [3, 5]]])
my_tensor.size()
# torch.Size([4, 3, 2])
my_tensor.size(dim=0)
my_tensor.size(dim=-3)
# 4
my_tensor.size(dim=1)
my_tensor.size(dim=-2)
my_tensor[0].size(dim=0)
my_tensor[0].size(dim=-2)
# 3
my_tensor.size(dim=2)
my_tensor.size(dim=-1)
my_tensor[0].size(dim=1)
my_tensor[0].size(dim=-1)
my_tensor[0][0].size(dim=0)
my_tensor[0][0].size(dim=-1)
# 2
my_tensor[0].size()
# torch.Size([3, 2])
my_tensor[0][0].size()
# torch.Size([2])
my_tensor[0][0][0].size()
# torch.Size([])
item() can get a standard Python number from the 0D or more D tensor of only one element as shown below:
*Memos:
-
item()can be used with a tensor but not withtorch. - A tensor must be a scalar.
import torch
my_tensor = torch.tensor(-3) # 0D tensor
my_tensor = torch.tensor([-3]) # 1D tensor
my_tensor = torch.tensor([[-3]]) # 2D tensor
my_tensor = torch.tensor([[[-3]]]) # 3D tensor
my_tensor.item()
# -3
tolist() can get a standard Python number or list from the 0D or more D tensor of zero or more elements as shown below. *tolist() can be used with a tensor but not with torch:
import torch
my_tensor = torch.tensor(-3) # 0D tensor
my_tensor.tolist()
# -3
my_tensor = torch.tensor([-3, 7, -5, 2, 6, 3]) # 1D tensor
my_tensor.tolist()
# [-3, 7, -5, 2, 6, 3]
my_tensor[0].tolist()
# -3
my_tensor = torch.tensor([[-3, 7, -5], [2, 6, 3], # 2D tensor
[8, 0, -1], [4, 9, -6]])
my_tensor.tolist()
# [[-3, 7, -5], [2, 6, 3],
# [8, 0, -1], [4, 9, -6]]
my_tensor[0].tolist()
# [-3, 7, -5]
my_tensor[0][0].tolist()
# -3
my_tensor = torch.tensor([[[-3, 7], [-5, 2], [6, 3]], # 3D tensor
[[8, 0], [-1, 4], [9, -6]],
[[5, -2], [-7, 9], [1, 1]],
[[6, -4], [0, -9], [3, 5]]])
my_tensor.tolist()
# [[[-3, 7], [-5, 2], [6, 3]],
# [[8, 0], [-1, 4], [9, -6]],
# [[5, -2], [-7, 9], [1, 1]],
# [[6, -4], [0, -9], [3, 5]]]
my_tensor[0].tolist()
# [[-3, 7], [-5, 2], [6, 3]]
my_tensor[0][0].tolist()
# [-3, 7]
my_tensor[0][0][0].tolist()
# -3
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