Defined in tensorflow/contrib/data/python/ops/

See the guide: Dataset Input Pipeline > Extra functions from

Returns the single element in dataset as a nested structure of tensors.

This function enables you to use a in a stateless "tensor-in tensor-out" expression, without creating a This can be useful when your preprocessing transformations are expressed as a Dataset, and you want to use the transformation at serving time. For example:

input_batch = tf.placeholder(tf.string, shape=[BATCH_SIZE])

def preprocessing_fn(input_str):
  # ...
  return image, label

dataset = (
           .map(preprocessing_fn, num_parallel_calls=BATCH_SIZE)

image_batch, label_batch =



A nested structure of tf.Tensor objects, corresponding to the single element of dataset.


  • TypeError: if dataset is not a object. InvalidArgumentError (at runtime): if dataset does not contain exactly one element.