DataFrameGroupByColumn

class pandas::DataFrameGroupByColumn

pandas C++ class.

Example

#include <pandas/pandas.h>
using namespace pandas;

// Use DataFrameGroupByColumn
DataFrameGroupByColumn obj;
// ... operations ...

Aggregation

Signature	Return Type	Location	Example
std::vector<T> transform(std::function<std::vector<T>(const std::vector<T>&)> fn) const	std::vector<T>	pd_groupby.h:704	View

Code Examples

The following examples are extracted from the test suite.

transform (pd_test_1_all.cpp:11071)

            std::cout << " -> tests passed" << std::endl;
        }

        void pd_test_func_apply_series_transform() {
            std::cout << "========= Series transform ============================";

            pandas::Series<double> s({1.0, 2.0, 3.0, 4.0}, "values");

            // Transform must return same shape
            auto result = s.transform([](double x) { return x * 2 + 1; });

            bool passed = true;
            if (result.size() != s.size()) {
                passed = false;
                std::cout << "  [FAIL] : in pd_test_func_apply_series_transform() : size changed" << std::endl;
                throw std::runtime_error("pd_test_func_apply_series_transform failed: size changed");
            }

            std::vector<double> expected = {3.0, 5.0, 7.0, 9.0};
            for (size_t i = 0; i < result.size(); ++i) {