将数据表拆分为多个固定大小的表 [英] Split datatable into multiple fixed sized tables

问题描述

我有一个包含1123条记录的数据表.我想将此表拆分为5个固定大小的单独数据表.每个表的大小限制为225.

I have a data table which has 1123 records. I want to split this table into 5 fixed size separate datatables. Size limit for each table is 225.

因此，结果数据表的大小将为:

So size of resulting datatables will be:

DT1 : 225 rows
DT2 : 225 rows
DT3 : 225 rows
DT4 : 225 rows
DT5 : 223 rows (remaining rows)

我能够找到如何使用LINQ根据列值拆分数据表

I was able to find how to split datatable based on the column value using LINQ here.

我还找到了一种将数据表拆分为多个表的方法

I also found a way to split datatable into multiple tables here. Wanted to know if there's a better way of doing this. Posting code form the link:

private static List<DataTable> SplitTable(DataTable originalTable, int batchSize)
{
     List<DataTable> tables = new List<DataTable>();
     int i = 0;
     int j = 1;
    DataTable newDt = originalTable.Clone();
   newDt.TableName = "Table_" + j;
   newDt.Clear();
    foreach (DataRow row in originalTable.Rows)
    {
         DataRow newRow = newDt.NewRow();
         newRow.ItemArray = row.ItemArray;
         newDt.Rows.Add(newRow);
         i++;
         if (i == batchSize)
        {
           tables.Add(newDt);
           j++;
          newDt = originalTable.Clone();
          newDt.TableName = "Table_" + j;
          newDt.Clear();
          i = 0;
      }
  }
   return tables;
}

需要帮助将数据表拆分为固定大小.

Need help in splitting datatable into fixed size.

推荐答案

我曾经做过这种扩展方法:

public static IEnumerable<IEnumerable<T>> ToChunks<T>(this IEnumerable<T> enumerable,
                                                      int chunkSize)
{
    int itemsReturned = 0;
    var list = enumerable.ToList(); // Prevent multiple execution of IEnumerable.
    int count = list.Count;
    while (itemsReturned < count)
    {
        int currentChunkSize = Math.Min(chunkSize, count - itemsReturned);
        yield return list.GetRange(itemsReturned, currentChunkSize);
        itemsReturned += currentChunkSize;
    }
}

将任何IEnumerable切成指定块大小的块.

that cuts any IEnumerable into chunks of the specified chunk size.

有了这个，您可以简单地做到:

Having this, you can simply do:

var tables = originalTable.AsEnumerable().ToChunks(225)
                          .Select(rows => rows.CopyToDataTable())

之所以能比简单的foreach更好，是因为list.GetRange是从列表中获取行范围的一种非常有效的方法.我很好奇您会发现什么.

The reason why this could perform better than a straightforward foreach is that list.GetRange is a very efficient method to get a range of rows from a list. I curious to know what you'll find out.

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