pytorch 给数据增加一个维度

使用 unsqueeze

>>> help(torch.squeeze)

Help on built-in function unsqueeze:

unsqueeze(...)
    unsqueeze(input, dim, out=None) -> Tensor
    
    Returns a new tensor with a dimension of size one inserted at the
    specified position.
    
    The returned tensor shares the same underlying data with this tensor.
    
    A :attr:`dim` value within the range ``[-input.dim() - 1, input.dim() + 1)``
    can be used. Negative :attr:`dim` will correspond to :meth:`unsqueeze`
    applied at :attr:`dim` = ``dim + input.dim() + 1``.
    
    Args:
        input (Tensor): the input tensor
        dim (int): the index at which to insert the singleton dimension
        out (Tensor, optional): the output tensor
    
    Example::
    
        >>> x = torch.tensor([1, 2, 3, 4])
        >>> torch.unsqueeze(x, 0)
        tensor([[ 1,  2,  3,  4]])
        >>> torch.unsqueeze(x, 1)
        tensor([[ 1],
                [ 2],
                [ 3],
                [ 4]])

也可以直接：

>>> a = torch.Tensor([1,2,3,4])
>>> a.unsqueeze(0)
tensor([[1., 2., 3., 4.]])