LINQ-以字符串形式存储的数字总和 [英] LINQ - Sum of numbers stored as string

问题描述

名称价格
ABC
B CBA
C 20
D 22
F 12
G 32
H 12

数据表将获得thease值，但我想获得Price列的总和.当字符串值将出现在行中时，它将被视为0，请为此提供解决方案.


谢谢，
Amod Kumar

Name Price
A ABC
B CBA
C 20
D 22
F 12
G 32
H 12

datatable will get thease value but i want to get the sum of Price column.when ever string value will be in row, It would be consider as a 0, Please provide solution for this.


Thanks,
Amod Kumar

推荐答案

以下LINQ语句对可以转换为int的值进行求和:

The following LINQ statement sums the values that can be converted into an int:

DataTable dt = ...
...
string col = "Price";
int sum = dt.AsEnumerable()
            .Aggregate(0,(n, r)=>
               {
                   int v;
                   return int.TryParse((r[col] as string) ?? string.Empty, out v)
                          ? n + v 
                          : n;
               }
             );

或者更容易阅读:

Or a bit easier to read:

DataTable dt = ...
...
int sum = dt.AsEnumerable().Aggregate(0,(n,r)=>PriceField(r)+n);
...
static int PriceField(DataRow r)
{
    int v;
    return int.TryParse((r["Price"] as string) ?? string.Empty, out v) ? v : 0;
}

或其他替代方法:

Or a further alternative:

DataTable dt = ...
...
int sum = dt.AsEnumerable().Aggregate(0,SumPriceField);
...
static int SumPriceField(int n, DataRow r)
{
    int v;
    return int.TryParse((r["Price"] as string) ?? string.Empty, out v) ? n + v : n;
}

干杯
Andi

Cheers
Andi

double SgAmount = (from DataRow row in dt.Rows
                            where Double.TryParse(row.Field<string>("Test"), out total_SG) == true
                            select total_SG).Sum();

下面是完整的，经过测试的示例代码.

The following is the complete working and tested sample code.

public static void main()
{
DataTable dt = new DataTable();
            dt.Columns.Add("Price");
            var dr = dt.NewRow();
            dr["Price"] = "12";
            dt.Rows.Add(dr);

            dr = dt.NewRow();
            dr["Price"] = "A1";
            dt.Rows.Add(dr);

            dr = dt.NewRow();
            dr["Price"] = "1";
            dt.Rows.Add(dr);

            dr = dt.NewRow();
            dr["Price"] = "2";
            dt.Rows.Add(dr);

            var sum = (from datarow in dt.AsEnumerable()
                       where (Program.NullableTryParseInt32(datarow["Price"].ToString()) != null)
                       select datarow["Price"]).ToArray().Sum(x => Convert.ToInt32(x));
} 

public static int? NullableTryParseInt32(string text)
       {
           int value;
           return int.TryParse(text, out value) ? (int?)value : null;
       }

让我知道这是否解决了您的问题.

let me know whether this solved your problem.

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