Tensor Transformations > Slicing and Joining
tf.one_hot(indices, depth, on_value=None, off_value=None, axis=None, dtype=None, name=None)
tf.one_hot(indices, depth, on_value=None, off_value=None, axis=None, dtype=None, name=None)
See the guide: Tensor Transformations > Slicing and Joining
Returns a one-hot tensor.
The locations represented by indices in indices
take value on_value
, while all other locations take value off_value
.
on_value
and off_value
must have matching data types. If dtype
is also provided, they must be the same data type as specified by dtype
.
If on_value
is not provided, it will default to the value 1
with type dtype
If off_value
is not provided, it will default to the value 0
with type dtype
If the input indices
is rank N
, the output will have rank N+1
. The new axis is created at dimension axis
(default: the new axis is appended at the end).
If indices
is a scalar the output shape will be a vector of length depth
If indices
is a vector of length features
, the output shape will be:
features x depth if axis == -1
depth x features if axis == 0
If indices
is a matrix (batch) with shape [batch, features]
, the output shape will be:
batch x features x depth if axis == -1
batch x depth x features if axis == 1
depth x batch x features if axis == 0
If dtype
is not provided, it will attempt to assume the data type of on_value
or off_value
, if one or both are passed in. If none of on_value
, off_value
, or dtype
are provided, dtype
will default to the value tf.float32
.
tf.string
, tf.bool
, etc.), both on_value
and off_value
must be provided to one_hot
.
Examples
Suppose that
indices = [0, 2, -1, 1]
depth = 3
on_value = 5.0
off_value = 0.0
axis = -1
Then output is [4 x 3]
:
output =
[5.0 0.0 0.0] // one_hot(0)
[0.0 0.0 5.0] // one_hot(2)
[0.0 0.0 0.0] // one_hot(-1)
[0.0 5.0 0.0] // one_hot(1)
Suppose that
indices = [[0, 2], [1, -1]]
depth = 3
on_value = 1.0
off_value = 0.0
axis = -1
Then output is [2 x 2 x 3]
:
output =
[
[1.0, 0.0, 0.0] // one_hot(0)
[0.0, 0.0, 1.0] // one_hot(2)
][
[0.0, 1.0, 0.0] // one_hot(1)
[0.0, 0.0, 0.0] // one_hot(-1)
]
Using default values for on_value
and off_value
:
indices = [0, 1, 2]
depth = 3
The output will be
output =
[[1., 0., 0.],
[0., 1., 0.],
[0., 0., 1.]]
Args:
indices
: ATensor
of indices.depth
: A scalar defining the depth of the one hot dimension.on_value
: A scalar defining the value to fill in output whenindices[j] = i
. (default: 1)off_value
: A scalar defining the value to fill in output whenindices[j] != i
. (default: 0)axis
: The axis to fill (default: -1, a new inner-most axis).dtype
: The data type of the output tensor.
Returns:
output
: The one-hot tensor.
Raises:
TypeError
: If dtype of eitheron_value
oroff_value
don't matchdtype
TypeError
: If dtype ofon_value
andoff_value
don't match one another
Defined in tensorflow/python/ops/array_ops.py
.