:github_url: https://github.com/pytorch/pytorch


.. _program_listing_file_torch_csrc_api_include_torch_data_transforms_stack.h:

Program Listing for File stack.h
================================

|exhale_lsh| :ref:`Return to documentation for file <file_torch_csrc_api_include_torch_data_transforms_stack.h>` (``torch/csrc/api/include/torch/data/transforms/stack.h``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   #pragma once
   
   #include <torch/data/example.h>
   #include <torch/data/transforms/collate.h>
   #include <torch/types.h>
   
   #include <utility>
   #include <vector>
   
   namespace torch::data::transforms {
   
   template <typename T = Example<>>
   struct Stack;
   
   template <>
   struct Stack<Example<>> : public Collation<Example<>> {
     Example<> apply_batch(std::vector<Example<>> examples) override {
       std::vector<torch::Tensor> data, targets;
       data.reserve(examples.size());
       targets.reserve(examples.size());
       for (auto& example : examples) {
         data.push_back(std::move(example.data));
         targets.push_back(std::move(example.target));
       }
       return {torch::stack(data), torch::stack(targets)};
     }
   };
   
   template <>
   struct Stack<TensorExample>
       : public Collation<Example<Tensor, example::NoTarget>> {
     TensorExample apply_batch(std::vector<TensorExample> examples) override {
       std::vector<torch::Tensor> data;
       data.reserve(examples.size());
       for (auto& example : examples) {
         data.push_back(std::move(example.data));
       }
       return torch::stack(data);
     }
   };
   } // namespace torch::data::transforms