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Huntzberger
Asked: 2020-08-10 11:14:20 +0800 CST 2020-08-10 11:14:20 +0800 CST

Show values ​​of a List<string> from a given index

  • 772

I have a query in which I fill a List with the values ​​of a column called Quantity, assuming that the values ​​of the list are the following:

Position= P value= v

p    v
[0] 41
[1] 42
[2] 43
[3] 44
[4] 45
[5] 46
[6] 47
[7] 9
[8] 10
[9] 11
[10] 12

And I have a variable value="45", and we see that in the list there is a value "45" and that its index is [4], so what I want now is to show the values ​​of the list starting at position 4. Here my code:

     string sql = "select * from MyTabla";
     SqlCommand cm = new SqlCommand(sql, con);
     SqlDataReader reader = cm.ExecuteReader();
     while (reader.Read())
       {
   array.Add(Convert.ToString(reader["Cantidad"]));
       }
       string valor= "45";
       if (array.Contains(valor))
       {
       int indice = array.IndexOf(valor);
       }
       foreach (string item in array)
       {
       //imprimir los valores del array apartir del valor de la variable indice
       }

c#

3 Answers

  1. Best Answer

    You can replace the foreachwith a forto be able to access through the index. 

               if (array.Contains(valor))
           {
             int indice = array.IndexOf(valor);
             for(int i = indice; i < array.Length;i++)
             {
              string e = array.ElementAt(i);
             //imprimir los valores del array apartir del valor de la variable indice
             }
           }
    • 0

  2. If you want to start from a particular index you could use the Skip function

    foreach (string item in array.Skip(indice)) {
   // código...
}

    Or use afor

    for (int i = indice; i <= array.Length; i++) {
   // código...
}
    • 0

  3. Add this reference:

    using System.Linq;

    Once done you can use this code:

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

            lst.Add("10");
            lst.Add("20");
            lst.Add("30");
            lst.Add("45");
            lst.Add("60");    

            var index = lst.IndexOf("45");
            var sublist = lst.Select((x, i) => new { Index = i, Value = x }).Where(item => item.Index >= index).ToList();

    Hope this can help you,

    Greetings.

    • 0