Question

我有2个pandas数据帧。第二个包含在第一个中。如何将第一个中的值替换为第二个中的值？

考虑这个例子：

df1 = pd.DataFrame(0, index=[1,2,3], columns=['a','b','c'])
df2 = pd.DataFrame(1, index=[1, 2], columns=['a', 'c'])

ris= [[1, 0, 1],
      [1, 0, 1],
      [0, 0, 0]]

和ris具有相同的d1

索引和列

可能的解决方案是：

for i in df2.index:
  for j in df2.columns:
     df1.loc[i, j] = df2.loc[i, j]

但这很丑陋

Answer 1

我认为您可以copy使用combine_first：

#include <pcl/io/obj_io.h>
#include <pcl/io/vtk_lib_io.h>
#include <pcl/console/print.h>
#include <pcl/console/parse.h>
#include <pcl/console/time.h>
#include <pcl/visualization/pcl_visualizer.h>
#include <pcl/PCLPointCloud2.h>
void
printHelp (int,
           char **argv)
{
  PCL_ERROR ("Please enter input.obj \n", argv[0]);
}

boost::shared_ptr<pcl::visualization::PCLVisualizer> simpleVis (pcl::PointCloud<pcl::PointXYZ>::ConstPtr cloud)
{
    // --------------------------------------------
    // -----Open 3D viewer and add point cloud-----
    // --------------------------------------------
    boost::shared_ptr<pcl::visualization::PCLVisualizer> viewer (new pcl::visualization::PCLVisualizer ("3D Viewer"));
    viewer->setBackgroundColor (0, 0, 0);
    viewer->addPointCloud<pcl::PointXYZ> (cloud, "sample cloud");
    viewer->setPointCloudRenderingProperties (pcl::visualization::PCL_VISUALIZER_POINT_SIZE, 1, "sample cloud");
    viewer->addCoordinateSystem (1.0);
    viewer->initCameraParameters ();
    return (viewer);
}
int
main (int argc,
      char** argv)
{
  PCL_INFO ("Display Obj file. For more information, use: %s -h\n", argv[0]);

  if (argc < 2)
  {
    printHelp (argc, argv);
    return (-1);
  }
  std::vector<int> obj_file_indices = pcl::console::parse_file_extension_argument (argc, argv, ".obj");
  if (obj_file_indices.size () != 1)
  {
    PCL_ERROR ("Need one input OBJ file.\n");
    return (-1);
  }
    pcl::PointCloud<pcl::PointXYZ>::Ptr Cloud_loaded (new pcl::PointCloud<pcl::PointXYZ> ());
    pcl::io::loadOBJFile (argv[obj_file_indices[0]], *Cloud_loaded);
    boost::shared_ptr<pcl::visualization::PCLVisualizer> viewer;
    viewer = simpleVis(Cloud_loaded);
   while (!viewer->wasStopped ()){
       viewer->spinOnce (100);
       boost::this_thread::sleep (boost::posix_time::microseconds (100000));
}
}

下一个解决方案是在df3 = df1.copy() df1[df2.columns] = df2[df2.columns] print df1.combine_first(df3) a b c 1 1.0 0 1.0 2 1.0 0 1.0 3 0.0 0 0.0中使用DataFrame和df4创建空的新index columns并填充加倍combine_first：

df1

Answer 2

尝试

{{1}}

如果列名称未知：

{{1}}

使用其他数据框更新值

2 个答案: