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Concatenates tensors along one dimension.

tf.concat( values, axis, name='concat' )

Concatenates the list of tensors `values`

along dimension `axis`

. If `values[i].shape = [D0, D1, ... Daxis(i), ...Dn]`

, the concatenated result has shape

[D0, D1, ... Raxis, ...Dn]

where

Raxis = sum(Daxis(i))

That is, the data from the input tensors is joined along the `axis`

dimension.

The number of dimensions of the input tensors must match, and all dimensions except `axis`

must be equal.

t1 = [[1, 2, 3], [4, 5, 6]] t2 = [[7, 8, 9], [10, 11, 12]] tf.concat([t1, t2], 0) # [[1, 2, 3], [4, 5, 6], [7, 8, 9], [10, 11, 12]] tf.concat([t1, t2], 1) # [[1, 2, 3, 7, 8, 9], [4, 5, 6, 10, 11, 12]] # tensor t3 with shape [2, 3] # tensor t4 with shape [2, 3] tf.shape(tf.concat([t3, t4], 0)) # [4, 3] tf.shape(tf.concat([t3, t4], 1)) # [2, 6]

As in Python, the `axis`

could also be negative numbers. Negative `axis`

are interpreted as counting from the end of the rank, i.e., `axis + rank(values)`

-th dimension.

t1 = [[[1, 2], [2, 3]], [[4, 4], [5, 3]]] t2 = [[[7, 4], [8, 4]], [[2, 10], [15, 11]]] tf.concat([t1, t2], -1)

would produce:

[[[ 1, 2, 7, 4], [ 2, 3, 8, 4]], [[ 4, 4, 2, 10], [ 5, 3, 15, 11]]]

Note:If you are concatenating along a new axis consider using stack. E.g.

tf.concat([tf.expand_dims(t, axis) for t in tensors], axis)

can be rewritten as

tf.stack(tensors, axis=axis)

Args | |
---|---|

`values` | A list of `Tensor` objects or a single `Tensor` . |

`axis` | 0-D `int32` `Tensor` . Dimension along which to concatenate. Must be in the range `[-rank(values), rank(values))` . As in Python, indexing for axis is 0-based. Positive axis in the rage of `[0, rank(values))` refers to `axis` -th dimension. And negative axis refers to `axis + rank(values)` -th dimension. |

`name` | A name for the operation (optional). |

Returns | |
---|---|

A `Tensor` resulting from concatenation of the input tensors. |

© 2020 The TensorFlow Authors. All rights reserved.

Licensed under the Creative Commons Attribution License 3.0.

Code samples licensed under the Apache 2.0 License.

https://www.tensorflow.org/versions/r1.15/api_docs/python/tf/concat