pybind11—类，结构体

2019-02-11 本文已影响4人侠之大者_7d3f

前言

在C++代码中， 类(class)的使用频率非常高, 类将数据和对数据的操作方法封装在一起，使得代码的抽象层次增加。如何将C++中定义好的类在python中调用?下面举例简单说明。

开发/测试环境

windows 10, 64bit
Anaconda3, with python 3.7
pycharm
visaul studio 2017

示例一

定义一个简单的类

class Student {

public:
    std::string name;
    std::string gender;
    int age;

public:
    Student() {}
    Student(std::string name, std::string gender, int age) {
        this->name = name;
        this->gender = gender;
        this->age = age;
    }
    ~Student() {};

public:
    //setter
    void setName(std::string name) {
        this->name = name;
    }

    void setGender(std::string gender) {
        this->gender = gender;
    }

    void setAge(int age) {
        this->age = age;
    }

    //getter
    std::string getName() {
        return this->name;
    }

    std::string getGender() {
        return this->gender;
    }

    int getAge() {
        return this->age;
    }

};

编写python扩展



PYBIND11_MODULE(example, m) {
    // Studnet
    py::class_<Student>(m, "Student")
        .def(py::init<std::string, std::string, int>())
        .def("setName", &Student::setName)
        .def("setGender", &Student::setGender)
        .def("setAge", &Student::setAge)
        .def("getName", &Student::getName)
        .def("getGender", &Student::getGender)
        .def("getAge", &Student::getAge);

}

编译生成python扩展

image.png

测试代码

image.png

静态方法

image.png

代码

class Student {

public:
    std::string name;
    std::string gender;
    int age;
    
public:
    Student() {}
    Student(std::string name, std::string gender, int age) {
        this->name = name;
        this->gender = gender;
        this->age = age;
    }
    ~Student() {};

public:
    //setter
    void setName(std::string name) {
        this->name = name;
    }

    void setGender(std::string gender) {
        this->gender = gender;
    }

    void setAge(int age) {
        this->age = age;
    }

    //getter
    std::string getName() {
        return this->name;
    }

    std::string getGender() {
        return this->gender;
    }

    int getAge() {
        return this->age;
    }

public:
    //声明静态成员
    static std::string university;

    // static method
    static std::string getUniversity() {
        return university;
    }

};

// 定义并且初始化static变量
std::string Student::university = "Xidian University";

PYBIND11_MODULE(example, m) {
    //py::class_<Pet>(m, "Pet")
    //  .def(py::init<const std::string &>())
    //  .def("setName", &Pet::setName)
    //  .def("getName", &Pet::getName);

    // Studnet
    py::class_<Student>(m, "Student")
        .def(py::init<std::string, std::string, int>())
        .def("setName", &Student::setName)
        .def("setGender", &Student::setGender)
        .def("setAge", &Student::setAge)
        .def("getName", &Student::getName)
        .def("getGender", &Student::getGender)
        .def("getAge", &Student::getAge)
        .def_static("getUniversity", &Student::getUniversity);  //def_static() 静态方法

}

image.png

例子2

定义一个Person类, 包含：

无参构造函数
含参构造函数
private成员变量
public成员变量
static静态成员变量
static静态函数
setter/getter函数


class Person
{

public:
    std::string habbit;             //兴趣爱好

private:
    std::string name;               //姓名
    std::string gender;             //性别
    int age;                        //年龄
    std::string idCardNum;          //身份证号码
    std::string address;            //住址

public:
    void setName(std::string name) {
        this->name = name;
    }

    void setAge(int age) {
        this->age = age;
    }

    void setGender(std::string gender) {
        this->gender = gender;
    }

    void setAddress(std::string address) {
        this->address = address;
    }

    void setIdCardNum(std::string idCardNum) {
        this->idCardNum = idCardNum;
    }

    std::string getName() {
        return this->name;
    }

    std::string getGender() {
        return this->gender;
    }

    int getAge() {
        return this->age;
    }

    std::string getAddress() {
        return this->address;
    }

    std::string getIdCardNum() {
        return this->idCardNum;
    }


public:
    //
    static std::string university;
    static std::string getUniversity() {
        return university;
    }

public:
    Person() {};
    Person(std::string name, std::string gender, int age) {
        this->name = name;
        this->gender = gender;
        this->age = age;
    }
    ~Person() {};

};

std::string Person::university = "xidian University";

python扩展代码

def(py::init()) python中构造方法，无参数
.def(py::init<std::string, std::string, int>()) 构造方法，含参数
.def("setName", &Person::setName) set()方法
.def("getName", &Person::getName) get()方法
.def_static("getUniversity", &Person::getUniversity) static静态方法
.def_readonly_static("university", &Person::university) static静态只读成员
.def_readwrite("habbit", &Person::habbit) 可读可写成员

对于C++ class中private成员：

image.png

.def_property("name", &Person::getName, &Person::setName)
        .def_property("age", &Person::getAge, &Person::setAge)
        .def_property("gender", &Person::getGender, &Person::setGender)
        .def_property("address", &Person::getAddress, &Person::setAddress)
        .def_property("idCardNum", &Person::getIdCardNum, &Person::setIdCardNum);

完整代码

#include<iostream>
#include<pybind11/pybind11.h>

namespace py = pybind11;

class Person
{

public:
    std::string habbit;             //兴趣爱好

private:
    std::string name;               //姓名
    std::string gender;             //性别
    int age;                        //年龄
    std::string idCardNum;          //身份证号码
    std::string address;            //住址

public:
    void setName(std::string name) {
        this->name = name;
    }

    void setAge(int age) {
        this->age = age;
    }

    void setGender(std::string gender) {
        this->gender = gender;
    }

    void setAddress(std::string address) {
        this->address = address;
    }

    void setIdCardNum(std::string idCardNum) {
        this->idCardNum = idCardNum;
    }

    std::string getName() {
        return this->name;
    }

    std::string getGender() {
        return this->gender;
    }

    int getAge() {
        return this->age;
    }

    std::string getAddress() {
        return this->address;
    }

    std::string getIdCardNum() {
        return this->idCardNum;
    }


public:
    //
    static std::string university;
    static std::string getUniversity() {
        return university;
    }

public:
    Person() {};
    Person(std::string name, std::string gender, int age) {
        this->name = name;
        this->gender = gender;
        this->age = age;
    }
    ~Person() {};

};

std::string Person::university = "xidian University";


PYBIND11_MODULE(demo3, m) {

    m.doc() = "Simple Class";
    
    py::class_<Person>(m, "Person")
        .def(py::init())
        .def(py::init<std::string, std::string, int>())
        .def("setName", &Person::setName)
        .def("setAge", &Person::setAge)
        .def("setGender", &Person::setGender)
        .def("setAddress", &Person::setAddress)
        .def("getName", &Person::getName)
        .def("getAge", &Person::getAge)
        .def("getGender", &Person::getGender)
        .def("getAddress", &Person::getAddress)
        .def_static("getUniversity", &Person::getUniversity)
        .def_readonly_static("university", &Person::university)
        .def_readwrite("habbit", &Person::habbit)
        .def_property("name", &Person::getName, &Person::setName)
        .def_property("age", &Person::getAge, &Person::setAge)
        .def_property("gender", &Person::getGender, &Person::setGender)
        .def_property("address", &Person::getAddress, &Person::setAddress)
        .def_property("idCardNum", &Person::getIdCardNum, &Person::setIdCardNum);


}

在pycharm中测试

将vs生成的lib和pyd文件复制到python代码所在目录，直接import即可：

image.png

python代码

person1 = demo3.Person()
person1.name = 'tianyu'
person1.age = 23
person1.gender = 'female'
print(person1.getName())
print(person1.getAge())
print(person1.getGender())
print(person1.university)

测试结果

image.png

pybind11—类，结构体

前言

开发/测试环境

示例一

例子2

在pycharm中测试

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