# tensorplay.functional.narrow

Source: https://www.tensorplay.cn/docs/generated/tensorplay.functional.narrow.html

```python
tensorplay.functional.narrow(input, dim, start, length) → Tensor
```

Returns a new tensor that is a narrowed version of input tensor. The
dimension dim is input from start to start + length. The
returned tensor and input tensor share the same underlying storage.

Parameters:

- input ([Tensor](/docs/generated/tensorplay.Tensor.html#tensorplay.Tensor)) – the tensor to narrow

- dim ([int](https://docs.python.org/3/builtins/functions.html#int)) – the dimension along which to narrow

- start ([int](https://docs.python.org/3/builtins/functions.html#int) or [Tensor](/docs/generated/tensorplay.Tensor.html#tensorplay.Tensor)) – index of the element to start the narrowed dimension from. Can be negative, which means indexing from the end of dim. If Tensor, it must be an 0-dim integral Tensor (bools not allowed)

- length ([int](https://docs.python.org/3/builtins/functions.html#int)) – length of the narrowed dimension, must be weakly positive

Example:

```
>>> x = tensorplay.tensor([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
>>> tensorplay.narrow(x, 0, 0, 2)
tensor([[ 1,  2,  3],
        [ 4,  5,  6]])
>>> tensorplay.narrow(x, 1, 1, 2)
tensor([[ 2,  3],
        [ 5,  6],
        [ 8,  9]])
>>> tensorplay.narrow(x, -1, tensorplay.tensor(-1), 1)
tensor([[3],
        [6],
        [9]])
```