Question

我有这段代码：

List<string> lineList = new List<string>();

foreach (var line in theFinalList)
{
    if (line.PartDescription != "")
        lineList.Add(line.PartDescription + " " + line.PartNumber + "\n");
    else
        lineList.Add("N/A " + line.PartNumber + "\n");

    //
    //This is what I am trying to fix:
    if (lineList.Contains("FID") || lineList.Contains("EXCLUDE"))
        // REMOVE THE item in the lineList
}

我正在尝试在foreach循环中浏览theFinalList并将每行添加到名为lineList的新列表中。添加后，我想删除该列表中包含 “FID” 或 “EXCLUDE”

我无法删除该条目，有人可以帮助我吗？

Answer 1

为什么要在以后删除它们时添加它们：

lineList = theFinalList.Select( line => 
{
    if (line.PartDescription != "")
        return line.PartDescription + " " + line.PartNumber + "\n";
    else
        return "N/A " + line.PartNumber + "\n";
})
.Where(x => !(x.Contains("FID") || x.Contains("EXCLUDE")))
.ToList();

Answer 2

以下代码示例遍历lineList并删除包含FID或EXCLUDE的行。

for(int i = lineList.Count - 1; i >= 0; i--)
{
    if (lineList[i].Contains("FID") || lineList[i].Contains("EXCLUDE"))
       lineList.RemoveAt(i);
}

删除项目时，以相反的顺序遍历列表非常重要。

Answer 3

当您在theFinalList循环中迭代theFinalList时，无法删除foreach列表中的项目。在这种情况下，您可能会收到System.InvalidOperationException消息“集合已被修改;枚举操作可能无法执行。“

你必须做这样的事情：

List<string> removals = new List<string>();

foreach (string s in theFinalList)
{
    //do stuff with (s);
    removals.Add(s);
}

foreach (string s in removals)
{
    theFinalList.Remove(s);
}

Answer 4

试

foreach (var line in theFinalList)
{
    string T = "";
    if (line.PartDescription != "")
        T = line.PartDescription + " " + line.PartNumber + "\n";
    else
        T = "N/A " + line.PartNumber + "\n";

    if (!(T.Contains("FID") || T.Contains("EXCLUDE"))
        lineList.Add (T);
}

Answer 5

试试这个：

var excludingTexts = new [] { "FID", "EXCLUDE" }
lineList = lineList.Where(y => !excludingTexts.Any(x => line.PartDescription.Contains(x) || line.PartNumber.Contains(x))).ToList();

或者您可以将其重写为：

var excludingTexts = new [] { "FID", "EXCLUDE" }
List<string> lineList = (from line in theFinalList
                         where !excludingTexts.Any(x => line.PartDescription.Contains(x) || line.PartNumber.Contains(x))
                         select line.PartDescription != "" ? 
                                line.PartDescription + " " + line.PartNumber + "\n" : 
                                "N/A " + line.PartNumber + "\n"
                         ).ToList();

Answer 6

我认为它更合乎逻辑的方法

Regex exclude = new Regex("FID|EXCLUDE");
foreach (var line in theFinalList.Where(
 ln => !exclude.Match(ln.PartDescription).Success && 
       !exclude.Match(ln.PartNumber ).Success))){

    string partDescription = "N/A";
    if(!string.IsNullOrWhiteSpace(line.PartDescription)){
        partDescription = line.PartDescription;
    }
    lineList.Add(partDescription  + " " + line.PartNumber + "\n");
}

根据您的需要编辑正则表达式（忽略大小写或多行，也可能编译）并随意用"\n"替换Environment.NewLine

字符串列表删除

6 个答案: