Add select methods

gammasoft71 · Dec 26, 2024 · 3835340 · 3835340
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diff --git a/src/xtd.core/include/xtd/collections/generic/extensions/enumerable.hpp b/src/xtd.core/include/xtd/collections/generic/extensions/enumerable.hpp
@@ -185,6 +185,24 @@ namespace xtd {
             return xtd::linq::enumerable::average(base());
           }
 
+          /// @brief Projects each element of a sequence into a new form.
+          /// @param source A sequence of values to invoke a transform function on.
+          /// @param selector A transform function to apply to each element.
+          /// @return An xtd::collections::generic::ienumerable <type_t> whose elements are the result of invoking the transform function on each element of source.
+          template<typename result_t>
+          const xtd::collections::generic::ienumerable<result_t>& select(const std::function<result_t(const source_t&)>& selector) const {
+            return xtd::linq::enumerable::select<source_t, result_t>(base(), selector);
+          }
+
+          /// @brief Projects each element of a sequence into a new form.
+          /// @param source A sequence of values to invoke a transform function on.
+          /// @param selector A transform function to apply to each element.
+          /// @return An xtd::collections::generic::ienumerable <type_t> whose elements are the result of invoking the transform function on each element of source.
+          template<typename result_t, typename selector_t>
+          const xtd::collections::generic::ienumerable<result_t>& select(const selector_t& selector) const {
+            return xtd::linq::enumerable::select<source_t, result_t>(base(), selector);
+          }
+
           /// @brief Creates a xtd::collections::generic::list <type_t> from an xtd::collections::generic::ienumerable <type_t>.
           /// @return A xtd::collections::generic::list <type_t> that contains elements from the input sequence.
           const xtd::collections::generic::list<source_t>& to_list() const noexcept;

diff --git a/src/xtd.core/include/xtd/linq/enumerable.hpp b/src/xtd.core/include/xtd/linq/enumerable.hpp
@@ -878,6 +878,90 @@ namespace xtd {
       /// @exception xtd::argument_out_of_range_exception `count` is less than 0.
       static const xtd::collections::generic::ienumerable<xtd::int32>& range(xtd::int32 start, xtd::int32 count);
 
+      /// @brief Projects each element of a sequence into a new form.
+      /// @param source A sequence of values to invoke a transform function on.
+      /// @param selector A transform function to apply to each element.
+      /// @return An xtd::collections::generic::ienumerable <type_t> whose elements are the result of invoking the transform function on each element of source.
+      template<typename source_t, typename result_t>
+      static const xtd::collections::generic::ienumerable<result_t>& select(const xtd::collections::generic::ienumerable<source_t>& source, const std::function<result_t(const source_t&)>& selector) {
+        static thread_local auto result = enumerable_collection<result_t> {};
+        result = enumerable_collection<result_t> {};
+        for (const auto& item : source)
+          result.items.push_back(selector(item));
+        return result;
+      }
+      /// @brief Projects each element of a sequence into a new form.
+      /// @param source A sequence of values to invoke a transform function on.
+      /// @param selector A transform function to apply to each element.
+      /// @return An xtd::collections::generic::ienumerable <type_t> whose elements are the result of invoking the transform function on each element of source.
+      template<typename source_t, typename result_t>
+      static const xtd::collections::generic::ienumerable<result_t>& select(const std::initializer_list<source_t>& source, const std::function<result_t(const source_t&)>& selector) {
+        static thread_local auto result = enumerable_collection<result_t> {};
+        result = enumerable_collection<result_t> {};
+        for (const auto& item : source)
+          result.items.push_back(selector(item));
+        return result;
+      }
+      /// @brief Projects each element of a sequence into a new form.
+      /// @param source A sequence of values to invoke a transform function on.
+      /// @param selector A transform function to apply to each element.
+      /// @return An xtd::collections::generic::ienumerable <type_t> whose elements are the result of invoking the transform function on each element of source.
+      template<typename source_t, typename result_t, typename collection_t>
+      static const xtd::collections::generic::ienumerable<result_t>& select(const collection_t& source, const std::function<result_t(const source_t&)>& selector) {
+        static thread_local auto result = enumerable_collection<result_t> {};
+        result = enumerable_collection<result_t> {};
+        for (const auto& item : source)
+          result.items.push_back(selector(item));
+        return result;
+      }
+      /// @brief Projects each element of a sequence into a new form.
+      /// @param source A sequence of values to invoke a transform function on.
+      /// @param selector A transform function to apply to each element.
+      /// @return An xtd::collections::generic::ienumerable <type_t> whose elements are the result of invoking the transform function on each element of source.
+      template<typename source_t, typename result_t, typename input_iterator_t>
+      static const xtd::collections::generic::ienumerable<result_t>& select(input_iterator_t first, input_iterator_t last, const std::function<result_t(const source_t&)>& selector) {
+        static thread_local auto result = enumerable_collection<result_t> {};
+        result = enumerable_collection<result_t> {};
+        for (auto iterator = first; iterator != last; ++iterator)
+          result.items.push_back(selector(*iterator));
+        return result;
+      }
+
+      /// @brief Projects each element of a sequence into a new form.
+      /// @param source A sequence of values to invoke a transform function on.
+      /// @param selector A transform function to apply to each element.
+      /// @return An xtd::collections::generic::ienumerable <type_t> whose elements are the result of invoking the transform function on each element of source.
+      template<typename source_t, typename result_t, typename selector_t>
+      static const xtd::collections::generic::ienumerable<result_t>& select(const xtd::collections::generic::ienumerable<source_t>& source, const selector_t& selector) {
+        return select(source, std::function<result_t(const source_t&)> {selector});
+      }
+      /// @brief Projects each element of a sequence into a new form.
+      /// @param source A sequence of values to invoke a transform function on.
+      /// @param selector A transform function to apply to each element.
+      /// @return An xtd::collections::generic::ienumerable <type_t> whose elements are the result of invoking the transform function on each element of source.
+      template<typename source_t, typename result_t, typename selector_t>
+      static const xtd::collections::generic::ienumerable<result_t>& select(const std::initializer_list<source_t>& source, const selector_t& selector) {
+        return select(source, std::function<result_t(const source_t&)> {selector});
+      }
+      /// @brief Projects each element of a sequence into a new form.
+      /// @param source A sequence of values to invoke a transform function on.
+      /// @param selector A transform function to apply to each element.
+      /// @return An xtd::collections::generic::ienumerable <type_t> whose elements are the result of invoking the transform function on each element of source.
+      template<typename result_t, typename collection_t, typename selector_t>
+      static const xtd::collections::generic::ienumerable<result_t>& select(const collection_t& source, const selector_t& selector) {
+        using source_t = typename collection_t::value_type;
+        return select(source, std::function<result_t(const source_t&)> {selector});
+      }
+      /// @brief Projects each element of a sequence into a new form.
+      /// @param source A sequence of values to invoke a transform function on.
+      /// @param selector A transform function to apply to each element.
+      /// @return An xtd::collections::generic::ienumerable <type_t> whose elements are the result of invoking the transform function on each element of source.
+      template<typename result_t, typename input_iterator_t, typename selector_t>
+      static const xtd::collections::generic::ienumerable<result_t>& select(input_iterator_t first, input_iterator_t last, const selector_t& selector) {
+        using source_t = typename std::decay<decltype(*first)>::type;
+        return select(first, last, std::function<result_t(const source_t&)> {selector});
+      }
+
       /// @brief Creates a xtd::collections::generic::list <type_t> from an xtd::collections::generic::ienumerable <type_t>.
       /// @param source The xtd::collections::generic::ienumerable <type_t> to create a xtd::collections::generic::list <type_t> from.
       /// @return A xtd::collections::generic::list <type_t> that contains elements from the input sequence.