问题
Given the following tensor (or any random tensor with two dimension), I want to get the index of '101':
tens = tensor([[ 101, 146, 1176, 21806, 1116, 1105, 18621, 119, 102, 0,
0, 0, 0],
[ 101, 1192, 1132, 1136, 1184, 146, 1354, 1128, 1127, 117,
1463, 119, 102],
[ 101, 6816, 1905, 1132, 14918, 119, 102, 0, 0, 0,
0, 0, 0]])
From the related answers I know that I can do something like this:
idxs = torch.tensor([(i == 101).nonzero() for i in tens])
But this seems messy and potentially quite slow. Is there a better way to do this that is fast and more torch-y?
Related questions discussing only one-dimensional tensor:
- How Pytorch Tensor get the index of specific value
- How Pytorch Tensor get the index of elements?
回答1:
How about (tens == 101).nonzero()[:, 1]
In [20]: from torch import tensor
In [21]: tens = torch.tensor([[ 101, 146, 1176, 21806, 1116, 1105, 18621, 119, 102, 0,
...: 0, 0, 0],
...: [ 101, 1192, 1132, 1136, 1184, 146, 1354, 1128, 1127, 117,
...: 1463, 119, 102],
...: [ 101, 6816, 1905, 1132, 14918, 119, 102, 0, 0, 0,
...: 0, 0, 0]])
In [22]: (tens == 101).nonzero()[:, 1]
Out[22]: tensor([0, 0, 0])
来源：https://stackoverflow.com/questions/59908433/pytorch-get-indices-of-value-in-two-dimensional-tensor