过滤数据表中的行 [英] Filtering rows in a datatable

问题描述

大家好，



我正在尝试按给定标准过滤数据表中的行：



（1）如果列的值不是白色，则应在数据表中看到行。

（2）如果满足规则1，则必须添加前2行和后2行。



前者;



输入

LineNumber描述颜色

0001 -------- aas ---白色

0002 ------- brrf ---白色

0003 -------- vea ---白色

0004 ------ adwec ---白色

0005- ----- 45fca ---绿色

0006 ----- fvsdca ---白色

0007 ----- rtvsca ---白色

0008 ----- 4dsdea ---白色



输出

LineNumber Desc颜色

0003 -------- vea ---白色

0004 ------ adwec ---白色

0005 ------ 45fca ---绿色

0006 ----- fvsdca ---白色

0007 ----- rtvsca-- -White



到目前为止我尝试了什么？

  var  result = 来自 r   dtOld.AsEnumerable （）
 其中 r.Field< string>（ 颜色）！=  白色 
 选择 r.Field< string>（  Line＃）; 
 
 List< int> lstIntOld =  new  List< int>（）; 
  foreach （ var  item  in  result）
 {
  int  numberAdd = Convert.ToInt32（item.ToString（）。TrimStart（'  0'））; 
 lstIntOld.Add（numberAdd  -   2 ）; 
 lstIntOld.Add（numberAdd  -   1 ）; 
 lstIntOld.Add（numberAdd）; 
 lstIntOld.Add（numberAdd +  1 ）; 
 lstIntOld.Add（numberAdd +  2 ）; 
} 
 
 lstIntOld = lstIntOld.Distinct（）。其中​​（ix = >  ix >  =  0 ）。ToList（）; 

我找到了我应该添加的行号并将它们放到列表中。现在我将通过匹配该列表中的那些数字来过滤数据表。但有更清洁或更好的方法来实现这个目标吗？



提前致谢

解决方案

我的赞美为了你提出你的问题！



这就是我要做的 - 或者至少我的第一次第二次迭代 * 。请注意，没有dtNew - 我只是从dtOld中删除不需要的行。如果你想保留dtOld，就必须复制行。

  int  inclusionSpan =  2 ; 
  bool  [] keepRow =  new   bool [dtOld.Rows.Count + inclusionSpan *  2 ]; 
  int  colorColumnIndex = dtOld.Columns.IndexOf（ 颜色）; 
 
  for （ int  rowIndex =  0 ; rowIndex <  dtOld.Rows.Count; rowIndex ++）
 {
  if （dtOld.Rows [rowIndex] .Field< string>（colorColumnIndex）！=   White ）
 {
  for （ int  includeOffset =  0 ; includeOffset <  = inclusionSpan *  2 ; includeOffset ++ ）
 keepRow [rowIndex + includeOffset] =  true ; 
 
 rowIndex + = inclusionSpan; 
} 
} 
 
  for （ int  rowIndex = dtOld.Rows.Count  -   1 ; rowIndex >  =  0 ; rowIndex--）
 {
  if （！keepRow [rowIndex + inclusionSpan]）
 dtOld。 Rows.RemoveAt（rowIndex位置）; 
} 

* ：累了，也许有一个包含span的地方有缺陷，必须要测试它

Hello all,

I am trying to filter rows in a datatable by the given criteria:

(1)The rows should be seen in datatable if the column has a value other than white.
(2)The former and latter 2 rows must be added as well if the rule 1 is met.

For ex;

Input
LineNumber Desc Color
0001--------aas---White
0002-------brrf---White
0003--------vea---White
0004------adwec---White
0005------45fca---Green
0006-----fvsdca---White
0007-----rtvsca---White
0008-----4dsdea---White

Output
LineNumber Desc Color
0003--------vea---White
0004------adwec---White
0005------45fca---Green
0006-----fvsdca---White
0007-----rtvsca---White

What I have tried so far?

var result = from r in dtOld.AsEnumerable()
             where r.Field<string>("Color") != "White"
             select r.Field<string>("Line#");

List<int> lstIntOld = new List<int>();
foreach (var item in result)
{
    int numberAdd = Convert.ToInt32(item.ToString().TrimStart('0'));
    lstIntOld.Add(numberAdd - 2);
    lstIntOld.Add(numberAdd - 1);
    lstIntOld.Add(numberAdd);
    lstIntOld.Add(numberAdd + 1);
    lstIntOld.Add(numberAdd + 2);
}

lstIntOld = lstIntOld.Distinct().Where(ix => ix >= 0).ToList();

I found the line numbers which I should add and put them to a list. Now I will filter the datatable by matching those numbers from that list. But is there a cleaner or better way to accomplish this?

Thanks in advance

解决方案

My compliment for your presentation of your question!

This is how I would do it - or at least my first second iteration *. Note there's no "dtNew" - I just remove the unwanted rows from "dtOld". If you want to keep "dtOld" around you would have to copy the rows.

int inclusionSpan = 2;
bool[] keepRow = new bool[dtOld.Rows.Count + inclusionSpan * 2];
int colorColumnIndex = dtOld.Columns.IndexOf("Color");

for (int rowIndex = 0; rowIndex < dtOld.Rows.Count; rowIndex++)
{
    if (dtOld.Rows[rowIndex].Field<string>(colorColumnIndex) != "White")
    {
        for (int includeOffset = 0; includeOffset <= inclusionSpan * 2; includeOffset++)
            keepRow[rowIndex + includeOffset] = true;

        rowIndex += inclusionSpan;
    }
}

for (int rowIndex = dtOld.Rows.Count - 1; rowIndex >= 0 ; rowIndex--)
{
    if (! keepRow[rowIndex + inclusionSpan])
        dtOld.Rows.RemoveAt(rowIndex);
}

* : Tired, maybe there's a flaw somewhere with the inclusionSpan, would have to test it.

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