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PartLayer[i]

represents a net layer that gives the i^(th) part of the input.

PartLayer[i;;j]

gives parts i through j.

PartLayer[i;;j;;k]

gives parts i through j in steps of k.

PartLayer[{spec1,spec2,…}]

takes part speci at level i in the input.

Details and Options
Details and Options Details and Options
Examples  
Basic Examples  
Scope  
Arguments  
Ports  
Possible Issues  
See Also
Tech Notes
Related Guides
History
Cite this Page

PartLayer

PartLayer[i]

represents a net layer that gives the i^(th) part of the input.

PartLayer[i;;j]

gives parts i through j.

PartLayer[i;;j;;k]

gives parts i through j in steps of k.

PartLayer[{spec1,spec2,…}]

takes part speci at level i in the input.

Details and Options

  • PartLayer[…][input] explicitly computes the output from applying the layer to input.
  • PartLayer[…][{input1,input2,…}] explicitly computes outputs for each of the inputi.
  • PartLayer exposes the following ports for use in NetGraph etc.:
  • "Input"an array
    "Output"an array
  • PartLayer is typically used inside NetChain, NetGraph, etc.
  • PartLayer normally infers the dimensions of its input from its context in NetChain etc. To specify the dimensions explicitly as {n1,n2,…}, use PartLayer["Input"->{n1,n2,…}].
  • PartLayer[i;;j] and PartLayer[i;;j;;k] give an output that is of the same rank as the input, whereas PartLayer[i] gives an output that is one rank smaller.
  • Information[PartLayer[…]] gives a report about the layer.
  • Information[PartLayer[…],prop] gives the value of the property prop of PartLayer[…]. Possible properties are the same as for NetGraph.

Examples

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Basic Examples  (2)

Create a PartLayer that takes the second part of an array:

Create a PartLayer that takes the second part of an array:

Apply the layer to a vector:

Scope  (6)

Arguments  (3)

Create a PartLayer that takes the first two elements:

Apply the layer to a matrix:

Create a PartLayer that takes the next-to-last element in an array:

Apply the layer to a vector:

Create a PartLayer that takes all elements after the second one:

Apply the layer to a vector:

This is equivalent to using All:

Ports  (3)

Create a PartLayer whose inputs are vectors of length three:

The layer threads across a batch of examples:

Create a PartLayer that takes the first column of its input, which is a matrix:

Apply the layer to a matrix:

Create a PartLayer that takes numbers at an odd place:

Apply the layer to a list of numbers:

Possible Issues  (1)

Using Part with a Span where the second index is smaller than the first is valid syntax, producing an empty list:

This is invalid syntax for PartLayer, as empty arrays are not allowed in nets:

Wolfram Research (2017), PartLayer, Wolfram Language function, https://reference.wolfram.com/language/ref/PartLayer.html (updated 2021).

Text

Wolfram Research (2017), PartLayer, Wolfram Language function, https://reference.wolfram.com/language/ref/PartLayer.html (updated 2021).

CMS

Wolfram Language. 2017. "PartLayer." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2021. https://reference.wolfram.com/language/ref/PartLayer.html.

APA

Wolfram Language. (2017). PartLayer. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/PartLayer.html

BibTeX

@misc{reference.wolfram_2025_partlayer, author="Wolfram Research", title="{PartLayer}", year="2021", howpublished="\url{https://reference.wolfram.com/language/ref/PartLayer.html}", note=[Accessed: 11-August-2025]}

BibLaTeX

@online{reference.wolfram_2025_partlayer, organization={Wolfram Research}, title={PartLayer}, year={2021}, url={https://reference.wolfram.com/language/ref/PartLayer.html}, note=[Accessed: 11-August-2025]}