C++读取numpy数据二进制文件

桃扇骨 2023-02-13 11:59 1阅读 0赞

# C++读取numpy数据二进制文件 #

--------------------

C++与Python中变量对应的精度类型:  
[https://docs.scipy.org/doc/numpy/user/basics.types.html\#array-types-and-conversions-between-types][https_docs.scipy.org_doc_numpy_user_basics.types.html_array-types-and-conversions-between-types]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2d1eXVlYWxpYW4_size_16_color_FFFFFF_t_70][]

### (1)将numpy数组保存为二进制文件 ###

def save_bin(data, bin_file, dtype="double"):
        """
        C++int对应Python np.intc
        C++float对应Python np.single
        C++double对应Python np.double
        :param data:
        :param bin_file:
        :param dtype:
        :return:
        """
        data = data.astype(np.double)
        data.astype(dtype).tofile(bin_file)

### (2)用numpy读取二进制文件 ###

def load_bin(bin_file, shape=None, dtype="double"):
        """
        :param bin_file:
        :param dtype:
        :return:
        """
        data = np.fromfile(bin_file, dtype=dtype)
        if shape:
            data = np.reshape(data, shape)
        return data
    
    if __name__ == "__main__":
        bin_file = "data.bin"
        shape = (2, 5)
        data1 = np.arange(10, 20).reshape(shape)
        save_bin(data1, bin_file)
        data2 = load_bin(bin_file, shape)
        print(data1)
        print(data2)

### (3)用C++读取二进制文件 ###

#include <iostream>
    #include <fstream>
    using namespace std;
    
    int main()
    {
      int row=2;
      int col=5;
      double fnum[row][col] = {0};
      ifstream in("bin/data.bin", ios::in | ios::binary);
      in.read((char *) &fnum, sizeof fnum);
      cout << in.gcount() << " bytes read\n";
      // show values read from file
      for(int i=0; i<row; i++){
          for(int j=0;j<col;j++){
                cout << fnum[i][j] << ",";
          }
           std::cout<<endl;
      }
      in.close();
      return 0;
    }

输出结果:

![20200529114850928.png][]

[https_docs.scipy.org_doc_numpy_user_basics.types.html_array-types-and-conversions-between-types]: https://docs.scipy.org/doc/numpy/user/basics.types.html#array-types-and-conversions-between-types
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2d1eXVlYWxpYW4_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20200529114416403.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2d1eXVlYWxpYW4=,size_16,color_FFFFFF,t_70
[20200529114850928.png]: https://img-blog.csdnimg.cn/20200529114850928.png