Substr

public final class Substr

Return substrings from `Tensor` of strings.

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: `strings.Substr` supports broadcasting up to two dimensions. More about broadcasting [here](http://docs.scipy.org/doc/numpy/user/basics.broadcasting.html)

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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.

Nested Classes

class Substr.Options Optional attributes for Substr  

Constants

String OP_NAME The name of this op, as known by TensorFlow core engine

Public Methods

Output<TString>
asOutput()
Returns the symbolic handle of the tensor.
static <T extends TNumber> Substr
create(Scope scope, Operand<TString> input, Operand<T> pos, Operand<T> len, Options... options)
Factory method to create a class wrapping a new Substr operation.
Output<TString>
output()
Tensor of substrings
static Substr.Options
unit(String unit)

Inherited Methods

Constants

public static final String OP_NAME

The name of this op, as known by TensorFlow core engine

Constant Value: "Substr"

Public Methods

public Output<TString> asOutput ()

Returns the symbolic handle of the tensor.

Inputs to TensorFlow operations are outputs of another TensorFlow operation. This method is used to obtain a symbolic handle that represents the computation of the input.

public static Substr create (Scope scope, Operand<TString> input, Operand<T> pos, Operand<T> len, Options... options)

Factory method to create a class wrapping a new Substr operation.

Parameters
scope current scope
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
options carries optional attributes values
Returns
  • a new instance of Substr

public Output<TString> output ()

Tensor of substrings

public static Substr.Options unit (String unit)

Parameters
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.