slice¶
-
paddle.fluid.layers.
slice
(input, axes, starts, ends)[source] This operator produces a slice of
input
along multiple axes. Similar to numpy: https://docs.scipy.org/doc/numpy/reference/arrays.indexing.html Slice usesaxes
,starts
andends
attributes to specify the start and end dimension for each axis in the list of axes and Slice uses this information to slice the input data tensor. If a negative value is passed tostarts
orends
such as \(-i\), it represents the reverse position of the axis \(i-1\) (here 0 is the initial position). If the value passed tostarts
orends
is greater than n (the number of elements in this dimension), it represents n. For slicing to the end of a dimension with unknown size, it is recommended to pass in INT_MAX. The size ofaxes
must be equal tostarts
andends
. Following examples will explain how slice works:Case1: Given: data = [ [1, 2, 3, 4], [5, 6, 7, 8], ] axes = [0, 1] starts = [1, 0] ends = [2, 3] Then: result = [ [5, 6, 7], ] Case2: Given: data = [ [1, 2, 3, 4], [5, 6, 7, 8], ] axes = [0, 1] starts = [0, 1] ends = [-1, 1000] # -1 denotes the reverse 0th position of dimension 0. Then: result = [ [2, 3, 4], ] # result = data[0:1, 1:4]
- Parameters
input (Variable) – A
Tensor
orLoDTensor
. The data type isfloat16
,float32
,float64
,int32
orint64
.axes (list|tuple) – The data type is
int32
. Axes that starts and ends apply to. It’s optional. If it is not provides, it will be treated as \([0,1,...,len(starts)-1]\).starts (list|tuple|Variable) – The data type is
int32
. Ifstarts
is a list or tuple, the elements of it should be integers or Tensors with shape [1]. Ifstarts
is an Variable, it should be an 1-D Tensor. It represents starting indices of corresponding axis inaxes
.ends (list|tuple|Variable) – The data type is
int32
. Ifends
is a list or tuple, the elements of it should be integers or Tensors with shape [1]. Ifends
is an Variable, it should be an 1-D Tensor . It represents ending indices of corresponding axis inaxes
.
- Returns
A
Tensor
orLoDTensor
. The data type is same asinput
.- Return type
Variable
- Raises
TypeError
– The type ofstarts
must be list, tuple or Variable.TypeError
– The type ofends
must be list, tuple or Variable.
Examples
import paddle.fluid as fluid input = fluid.data( name="input", shape=[4, 5, 6], dtype='float32') # example 1: # attr starts is a list which doesn't contain tensor Variable. axes = [0, 1, 2] starts = [-3, 0, 2] ends = [3, 2, 4] sliced_1 = fluid.layers.slice(input, axes=axes, starts=starts, ends=ends) # sliced_1 is input[0:3, 0:2, 2:4]. # example 2: # attr starts is a list which contain tensor Variable. minus_3 = fluid.layers.fill_constant([1], "int32", -3) sliced_2 = fluid.layers.slice(input, axes=axes, starts=[minus_3, 0, 2], ends=ends) # sliced_2 is input[0:3, 0:2, 2:4].