tensorflow:: ops:: Substr

Return substrings from Tensor of strings.

Summary

For each string in the input Tensor , creates a substring starting at index pos with a total length of len .

If len defines a substring that would extend beyond the length of the input string, or if len is negative, then as many characters as possible are used.

A negative pos indicates distance within the string backwards from the end.

If pos specifies an index which is out of range for any of the input strings, then an InvalidArgumentError is thrown.

pos and len must have the same shape, otherwise a ValueError is thrown on Op creation.

NOTE : Substr supports broadcasting up to two dimensions. More about broadcasting here

Examples

Using scalar pos and len :

input = [b'Hello', b'World']
position = 1
length = 3

output = [b'ell', b'orl']

Using pos and len with same shape as input :

input = [[b'ten', b'eleven', b'twelve'],
         [b'thirteen', b'fourteen', b'fifteen'],
         [b'sixteen', b'seventeen', b'eighteen']]
position = [[1, 2, 3],
            [1, 2, 3],
            [1, 2, 3]]
length =   [[2, 3, 4],
            [4, 3, 2],
            [5, 5, 5]]

output = [[b'en', b'eve', b'lve'],
          [b'hirt', b'urt', b'te'],
          [b'ixtee', b'vente', b'hteen']]

Broadcasting pos and len onto input :

input = [[b'ten', b'eleven', b'twelve'],
         [b'thirteen', b'fourteen', b'fifteen'],
         [b'sixteen', b'seventeen', b'eighteen'],
         [b'nineteen', b'twenty', b'twentyone']]
position = [1, 2, 3]
length =   [1, 2, 3]

output = [[b'e', b'ev', b'lve'],
          [b'h', b'ur', b'tee'],
          [b'i', b've', b'hte'],
          [b'i', b'en', b'nty']]

Broadcasting input onto pos and len :

input = b'thirteen'
position = [1, 5, 7]
length =   [3, 2, 1]

output = [b'hir', b'ee', b'n']

Raises:

• ValueError : If the first argument cannot be converted to a Tensor of dtype string .
• InvalidArgumentError : If indices are out of range.
• ValueError : If pos and len are not the same shape.

Args:

• scope: A Scope object
• input: Tensor of strings
• pos: Scalar defining the position of first character in each substring
• len: Scalar defining the number of characters to include in each substring

Optional attributes (see Attrs ):

• unit: The unit that is used to create the substring. One of: "BYTE" (for defining position and length by bytes) or "UTF8_CHAR" (for the UTF-8 encoded Unicode code points). The default is "BYTE" . Results are undefined if unit=UTF8_CHAR and the input strings do not contain structurally valid UTF-8.

Returns:

• Output : Tensor of substrings

Public attributes

Operation operation

::tensorflow::Output output

Public functions

 Substr(
  const ::tensorflow::Scope & scope,
  ::tensorflow::Input input,
  ::tensorflow::Input pos,
  ::tensorflow::Input len
)

 Substr(
  const ::tensorflow::Scope & scope,
  ::tensorflow::Input input,
  ::tensorflow::Input pos,
  ::tensorflow::Input len,
  const Substr::Attrs & attrs
)

::tensorflow::Node * node() const 

 operator::tensorflow::Input() const 

 operator::tensorflow::Output() const 

Public static functions

Attrs Unit(
  StringPiece x
)