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tf.data.experimental.assert_cardinality

Asserts the cardinality of the input dataset.

tf.data.experimental.assert_cardinality(
    expected_cardinality
)
Note: The following assumes that "examples.tfrecord" contains 42 records. 
dataset = tf.data.TFRecordDataset("examples.tfrecord")
cardinality = tf.data.experimental.cardinality(dataset)
print((cardinality == tf.data.experimental.UNKNOWN_CARDINALITY).numpy())
True
dataset = dataset.apply(tf.data.experimental.assert_cardinality(42))
print(tf.data.experimental.cardinality(dataset).numpy())
42
Args
expected_cardinality The expected cardinality of the input dataset.
Returns
A Dataset transformation function, which can be passed to tf.data.Dataset.apply.
Raises
FailedPreconditionError The assertion is checked at runtime (when iterating the dataset) and an error is raised if the actual and expected cardinality differ.

© 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/r2.3/api_docs/python/tf/data/experimental/assert_cardinality