我正在使用spark做一个项目。在某些阶段,我需要在单个数据帧中合并或连接3个数据帧。这些数据框来自spark sql表 我使用了联合函数,它已经从两个表合并了相同数字的列 但我也需要合并不相等的列值。我现在很困惑 有没有办法在pyspark中合并或连接不等列的数据框,请指导我
答案 0 :(得分:0)
您可以在合并之前添加一个具有默认值的列。
List<Images> ImageCollection;
private async void Button_Click(object sender, RoutedEventArgs e)
{
ImageCollection = new List<Images>();
// pick a folder
var folderPicker = new Windows.Storage.Pickers.FolderPicker();
folderPicker.FileTypeFilter.Add(".jpg");
var folder = await folderPicker.PickSingleFolderAsync();
var filesList = await folder.CreateFileQueryWithOptions(new QueryOptions(CommonFileQuery.DefaultQuery, new string[] { ".jpg", ".png", ".jpeg" })).GetFilesAsync();
for (int i = 0; i < filesList.Count; i++)
{
StorageFile imagefile = filesList[i];
BitmapImage bitmapimage = new BitmapImage();
using (IRandomAccessStream stream = await imagefile.OpenAsync(FileAccessMode.Read))
{
bitmapimage.SetSource(stream);
}
ImageCollection.Add(new Images()
{
ImageURL = bitmapimage,
ImageText = filesList[i].Name
});
}
AdaptiveGV.ItemsSource = ImageCollection;
}
}
public class Images
{
public ImageSource ImageURL { get; set; }
public string ImageText { get; set; }
}