JsonValue

class pandas::JsonValue

pandas C++ class.

Example

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

// Use JsonValue
JsonValue obj;
// ... operations ...

Constructors

Signature	Location	Example
JsonValue() = default	json.h:44	View
JsonValue(const JsonValue&) = default	json.h:45	View
JsonValue(JsonValue&&) noexcept = default	json.h:46	View

Type Checking

Signature	Return Type	Location	Example
bool is_array() const { return std::holds_alternative<JsonArray>(v)	bool	json.h:63
bool is_bool() const { return std::holds_alternative<bool>(v)	bool	json.h:59
bool is_double() const { return std::holds_alternative<double>(v)	bool	json.h:61
bool is_int() const { return std::holds_alternative<int64_t>(v)	bool	json.h:60	View
bool is_null() const { return std::holds_alternative<std::monostate>(v)	bool	json.h:58	View
bool is_object() const { return std::holds_alternative<JsonObject>(v)	bool	json.h:64	View
bool is_string() const { return std::holds_alternative<std::string>(v)	bool	json.h:62

Code Examples

The following examples are extracted from the test suite.

JsonValue (pd_test_5_all.cpp:81168)

void case_1_default_is_null(int& local_fail) {
    std::cout << "-- case_1_default_is_null\n";
    JsonValue v;
    pandas_tests::check(v.is_null(),
        "case_1_default_is_null.is_null()", local_fail);
}

void case_2_bool_true_false(int& local_fail) {
    std::cout << "-- case_2_bool_true_false\n";
    check_str("case_2_bool_true_false.true_str()",  "True",
              [] { return PIO::json_value_to_string(JsonValue(true)); }, local_fail);
    check_str("case_2_bool_true_false.false_str()", "False",
              [] { return PIO::json_value_to_string(JsonValue(false)); }, local_fail);
}

void case_3_int64_range(int& local_fail) {
    std::cout << "-- case_3_int64_range\n";
    check_str("case_3_int64_range.zero()", "0",
              [] { return PIO::json_value_to_string(JsonValue(int64_t{0})); },
              local_fail);
    check_str("case_3_int64_range.neg()", "-12345",

JsonValue (pd_test_5_all.cpp:81168)

void case_1_default_is_null(int& local_fail) {
    std::cout << "-- case_1_default_is_null\n";
    JsonValue v;
    pandas_tests::check(v.is_null(),
        "case_1_default_is_null.is_null()", local_fail);
}

void case_2_bool_true_false(int& local_fail) {
    std::cout << "-- case_2_bool_true_false\n";
    check_str("case_2_bool_true_false.true_str()",  "True",
              [] { return PIO::json_value_to_string(JsonValue(true)); }, local_fail);
    check_str("case_2_bool_true_false.false_str()", "False",
              [] { return PIO::json_value_to_string(JsonValue(false)); }, local_fail);
}

void case_3_int64_range(int& local_fail) {
    std::cout << "-- case_3_int64_range\n";
    check_str("case_3_int64_range.zero()", "0",
              [] { return PIO::json_value_to_string(JsonValue(int64_t{0})); },
              local_fail);
    check_str("case_3_int64_range.neg()", "-12345",

JsonValue (pd_test_5_all.cpp:81168)

void case_1_default_is_null(int& local_fail) {
    std::cout << "-- case_1_default_is_null\n";
    JsonValue v;
    pandas_tests::check(v.is_null(),
        "case_1_default_is_null.is_null()", local_fail);
}

void case_2_bool_true_false(int& local_fail) {
    std::cout << "-- case_2_bool_true_false\n";
    check_str("case_2_bool_true_false.true_str()",  "True",
              [] { return PIO::json_value_to_string(JsonValue(true)); }, local_fail);
    check_str("case_2_bool_true_false.false_str()", "False",
              [] { return PIO::json_value_to_string(JsonValue(false)); }, local_fail);
}

void case_3_int64_range(int& local_fail) {
    std::cout << "-- case_3_int64_range\n";
    check_str("case_3_int64_range.zero()", "0",
              [] { return PIO::json_value_to_string(JsonValue(int64_t{0})); },
              local_fail);
    check_str("case_3_int64_range.neg()", "-12345",

is_int (pd_test_5_all.cpp:81116)

static void check_lookup_int(const std::string& label,
                             const JsonObject& root,
                             const std::vector<std::string>& path,
                             int64_t expected_int,
                             int& local_fail) {
    bool ok = false;
    std::string err;
    try {
        const JsonValue* hit = PIO::lookup_path(root, path);
        if (hit && hit->is_int() && std::get<int64_t>(hit->v) == expected_int) {
            ok = true;
        }
    } catch (const std::exception& e) {
        err = std::string("THREW: ") + e.what();
    }
    pandas_tests::check(ok, label, local_fail);
    if (!ok && !err.empty()) std::cout << "  " << err << "\n";
}

static void check_lookup_object(const std::string& label,

is_null (pd_test_5_all.cpp:71470)

    bool ok = (got == expected);
    pandas_tests::check(ok, label, local_fail);
    if (!ok) {
        std::cout << "    expected: [" << expected << "]\n"
                  << "    got:      [" << got << "]\n";
    }
    return ok;
}

static numpy::object_ obj_none() {
    return numpy::object_();  // default-constructed -> is_null() == true
}

static numpy::object_ obj_nan() {
    return numpy::object_(std::numeric_limits<double>::quiet_NaN());
}

static numpy::object_ obj_int(int64_t v) {
    return numpy::object_(v);
}

is_object (pd_test_3_all.cpp:626)

        throw std::runtime_error("pd_test_3_all_index_dtype_checks failed: int is_numeric");
    }
    if (!int_dtype.is_integer()) {
        std::cout << "  [FAIL] : in pd_test_3_all_index_dtype_checks() : int should be integer" << std::endl;
        throw std::runtime_error("pd_test_3_all_index_dtype_checks failed: int is_integer");
    }
    if (int_dtype.is_floating()) {
        std::cout << "  [FAIL] : in pd_test_3_all_index_dtype_checks() : int should not be floating" << std::endl;
        throw std::runtime_error("pd_test_3_all_index_dtype_checks failed: int is_floating");
    }
    if (int_dtype.is_object()) {
        std::cout << "  [FAIL] : in pd_test_3_all_index_dtype_checks() : int should not be object" << std::endl;
        throw std::runtime_error("pd_test_3_all_index_dtype_checks failed: int is_object");
    }

    // Test with float index
    pandas::IndexDtype<double> float_dtype;
    if (!float_dtype.is_numeric()) {
        std::cout << "  [FAIL] : in pd_test_3_all_index_dtype_checks() : float should be numeric" << std::endl;
        throw std::runtime_error("pd_test_3_all_index_dtype_checks failed: float is_numeric");
    }