tf.lookup.TextFileInitializer

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Table initializers from a text file.

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Compat aliases for migration

See Migration guide for more details.

tf.compat.v1.lookup.TextFileInitializer

tf.lookup.TextFileInitializer(
    filename, key_dtype, key_index, value_dtype, value_index, vocab_size=None,
    delimiter='\t', name=None
)

This initializer assigns one entry in the table for each line in the file.

The key and value type of the table to initialize is given by key_dtype and value_dtype.

The key and value content to get from each line is specified by the key_index and value_index.

• TextFileIndex.LINE_NUMBER means use the line number starting from zero, expects data type int64.
• TextFileIndex.WHOLE_LINE means use the whole line content, expects data type string.
• A value >=0 means use the index (starting at zero) of the split line based on delimiter.

For example if we have a file with the following content:

import tempfile
f = tempfile.NamedTemporaryFile(delete=False)
content='\n'.join(["emerson 10", "lake 20", "palmer 30",])
f.file.write(content.encode('utf-8'))
f.file.close()

The following snippet initializes a table with the first column as keys and second column as values:

• emerson -> 10
• lake -> 20
• palmer -> 30

init= tf.lookup.TextFileInitializer(
   filename=f.name,
   key_dtype=tf.string, key_index=0,
   value_dtype=tf.int64, value_index=1,
   delimiter=" ")
table = tf.lookup.StaticHashTable(init, default_value=-1)
table.lookup(tf.constant(['palmer','lake','tarkus'])).numpy()

Similarly to initialize the whole line as keys and the line number as values.

• emerson 10 -> 0
• lake 20 -> 1
• palmer 30 -> 2

init = tf.lookup.TextFileInitializer(
  filename=f.name,
  key_dtype=tf.string, key_index=tf.lookup.TextFileIndex.WHOLE_LINE,
  value_dtype=tf.int64, value_index=tf.lookup.TextFileIndex.LINE_NUMBER,
  delimiter=" ")
table = tf.lookup.StaticHashTable(init, -1)
table.lookup(tf.constant('palmer 30')).numpy()
2

Args
filename	The filename of the text file to be used for initialization. The path must be accessible from wherever the graph is initialized (eg. trainer or eval workers). The filename may be a scalar Tensor.
key_dtype	The key data type.
key_index	the index that represents information of a line to get the table 'key' values from.
value_dtype	The value data type.
value_index	the index that represents information of a line to get the table 'value' values from.'
vocab_size	The number of elements in the file, if known.
delimiter	The delimiter to separate fields in a line.
name	A name for the operation (optional).

Raises
ValueError	when the filename is empty, or when the table key and value data types do not match the expected data types.

Attributes
key_dtype	The expected table key dtype.
value_dtype	The expected table value dtype.

Methods

initialize

View source

initialize(
    table
)

Initializes the table from a text file.

Args
table	The table to be initialized.

Returns
The operation that initializes the table.

Raises
TypeError	when the keys and values data types do not match the table key and value data types.