Question

在列表中，我根据特定条件获得了一些字符串值。我需要将字符串值与另一个字符串"SUM()"连接起来。

例如：列表包含值A1，A2，A3

输出字符串应为

总和（A1）为A1，总和（A2）为A2，总和（A3）为A3

我的代码如下：

List<string> strList = new List<string>();
foreach (DataRow dr in dt.Rows)
{
    strList .Add(dr[0].ToString());
}
string NewStrSum  = "";
string NewColSum = "";
NewStrSum = "  SUM(";
NewColSum = NewStrSum + String.Join(") ", strList .Select(n => n.ToString()).ToArray());

但输出为Sum（A1）A2

Answer 1

您可以使用Enumerable.Select获取指定格式的List<string>中的每个元素，并将其与string.Join结合使用，以,为其连接;

var list = new List<string>() {"A1", "A2", "A3"};
var newlist = list.Select(s => string.Format("SUM({0}) as {0}", s));
var result = string.Join(",", newlist);

result将是;

SUM(A1) as A1,SUM(A2) as A2,SUM(A3) as A3

Answer 2

为什么不使用这样的东西：

// Create your list
var list = new List<string>();
list.Add("A1");
list.Add("A2");
list.Add("A3");

// Create list of elements that look like 'Sum(X) as X':
var sumList = list.Select(x=>string.Format("Sum({0}) as {0}", x));

// Create single string
var result = string.Join(", ", sumList);
Console.WriteLine(result);

Answer 3

试试这个：

var list = new List<string> {"A1", "A2", "A3"};
var str = list.Aggregate(string.Empty, (current, item) => current + string.Format("SUM({0}) AS {0},", item));
str = str.Remove(str.Length - 1);

Answer 4

string result = string.Empty;

for(int i=0;i<strList.Count;i++)
{
    if(i!=0)
    result+= " , ";
    result+= "Sum("+strList[i]+") as "+strList[i];
}

Answer 5

尝试连接bucle foreach

中的字符串

这里有一个例子：

string OutPut  = string.Empty;
        foreach (DataRow dr in dt.Rows)
                {
                    OutPut += "SUM("
                            + dr[0].ToString()
                            + ") as ";
                            + dr[0].ToString()
                            +", "; 
                }

Answer 6

您可以按照以下方式使用

// This is your code
List<string> strList = new List<string>();
                foreach (DataRow dr in dt.Rows)
                {
                    strList .Add(dr[0].ToString());
                }

// New Code
string newColSum = string.Join(",", strList.Select(s => string.Format("SUM({0}) as {0}", s)));

需要在C＃windows

6 个答案: