tf.contrib.lookup.MutableHashTable

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Class MutableHashTable

A generic mutable hash table implementation.

Inherits From: LookupInterface

Data can be inserted by calling the insert method and removed by calling the remove method. It does not support initialization via the init method.

Example usage:

table = tf.lookup.MutableHashTable(key_dtype=tf.string, value_dtype=tf.int64,
                                   default_value=-1)
sess.run(table.insert(keys, values))
out = table.lookup(query_keys)
print(out.eval())

__init__

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__init__(
    key_dtype,
    value_dtype,
    default_value,
    name='MutableHashTable',
    checkpoint=True
)

Creates an empty MutableHashTable object.

Creates a table, the type of its keys and values are specified by key_dtype and value_dtype, respectively.

Args:

  • key_dtype: the type of the key tensors.
  • value_dtype: the type of the value tensors.
  • default_value: The value to use if a key is missing in the table.
  • name: A name for the operation (optional).
  • checkpoint: if True, the contents of the table are saved to and restored from checkpoints. If shared_name is empty for a checkpointed table, it is shared using the table node name.

Returns:

A MutableHashTable object.

Raises:

  • ValueError: If checkpoint is True and no name was specified.

Properties

key_dtype

The table key dtype.

name

The name of the table.

resource_handle

Returns the resource handle associated with this Resource.

value_dtype

The table value dtype.

Methods

export

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export(name=None)

Returns tensors of all keys and values in the table.

Args:

  • name: A name for the operation (optional).

Returns:

A pair of tensors with the first tensor containing all keys and the second tensors containing all values in the table.

insert

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insert(
    keys,
    values,
    name=None
)

Associates keys with values.

Args:

  • keys: Keys to insert. Can be a tensor of any shape. Must match the table's key type.
  • values: Values to be associated with keys. Must be a tensor of the same shape as keys and match the table's value type.
  • name: A name for the operation (optional).

Returns:

The created Operation.

Raises:

  • TypeError: when keys or values doesn't match the table data types.

lookup

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lookup(
    keys,
    name=None
)

Looks up keys in a table, outputs the corresponding values.

The default_value is used for keys not present in the table.

Args:

  • keys: Keys to look up. Can be a tensor of any shape. Must match the table's key_dtype.
  • name: A name for the operation (optional).

Returns:

A tensor containing the values in the same shape as keys using the table's value type.

Raises:

  • TypeError: when keys do not match the table data types.

remove

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remove(
    keys,
    name=None
)

Removes keys and its associated values from the table.

If a key is not present in the table, it is silently ignored.

Args:

  • keys: Keys to remove. Can be a tensor of any shape. Must match the table's key type.
  • name: A name for the operation (optional).

Returns:

The created Operation.

Raises:

  • TypeError: when keys do not match the table data types.

size

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size(name=None)

Compute the number of elements in this table.

Args:

  • name: A name for the operation (optional).

Returns:

A scalar tensor containing the number of elements in this table.