# tensorplay.nn.utils.rnn.pack_sequence

Source: https://www.tensorplay.cn/docs/generated/tensorplay.nn.utils.rnn.pack_sequence.html

```python
tensorplay.nn.utils.rnn.pack_sequence(sequences, enforce_sorted: bool = True) → PackedSequence
```

Packs a list of variable length Tensors.

Consecutive call of the next functions: pad_sequence, pack_padded_sequence.

sequences should be a list of Tensors of size L x *, where L is
the length of a sequence and * is any number of trailing dimensions,
including 0.

For unsorted sequences, use enforce_sorted = False. If enforce_sorted is
True, the sequences should be sorted in the order of decreasing length.
enforce_sorted = True is only necessary for ONNX export.

Example

```
>>> from tensorplay.nn.utils.rnn import pack_sequence
>>> a = tp.tensor([1, 2, 3])
>>> b = tp.tensor([4, 5])
>>> c = tp.tensor([6])
>>> pack_sequence([a, b, c])
PackedSequence(data=tensor([1, 4, 6, 2, 5, 3]), batch_sizes=tensor([3, 2, 1]), sorted_indices=None, unsorted_indices=None)
```

Parameters:

- sequences ([list](https://docs.python.org/3/builtins/stdtypes.html#list)[[Tensor](/docs/generated/tensorplay.Tensor.html#tensorplay.Tensor)]) – A list of sequences of decreasing length.

- enforce_sorted ([bool](https://docs.python.org/3/builtins/functions.html#bool), optional) – if True, checks that the input contains sequences sorted by length in a decreasing order. If False, this condition is not checked. Default: True.

Returns:

a [PackedSequence](/docs/generated/tensorplay.nn.utils.rnn.PackedSequence.html#tensorplay.nn.utils.rnn.PackedSequence) object