How to merge two LINQ in one?

Question

I have two Linq queries

dTable.AsEnumerable()
      .Where(s => Convert.ToString(s["OccpStat"]).ToLower().Equals("i"))
      .ToList()
      .ForEach(D => D.SetField("OccpStat", Convert.ToBoolean(1)));

dTable.AsEnumerable()
      .Where(s => Convert.ToString(s["OccpStat"]) != ("True"))
      .ToList()
      .ForEach(D => D.SetField("OccpStat", Convert.ToBoolean(0)));

Basically it work with DataTable and change value of cell if cell is "I" then 1 if not "I" then 0

Is there any chance of somehow merging them into one LINQ and just insert some If statement to it instead of looping twice through the same table with two linq queries?

Answer 1

Provided sample loops four times through DataTable : two times when calling ToList , and two times when calling ForEach .

The next approach can be used to rewrite two given LINQ queries into one, and it will loop two times through DataTable :

dTable.AsEnumerable()
    // First loop.
    .ToList()
    // Second loop.
    .ForEach(D => 
    {
        string OccpStat = Convert.ToString(D["OccpStat"]);

        if (OccpStat.ToLower().Equals("i"))
            D.SetField("OccpStat", Convert.ToBoolean(1));
        else
            D.SetField("OccpStat", Convert.ToBoolean(0));
    });

---

If you want to loop only once through DataTable then you should declare your own ForEach method and delete call to ToList method:

public static void ForEach<T>(this IEnumerable<T> items, Action<T> action)
{
    foreach (T t in items)
        action(t);
}

...

dTable.AsEnumerable()
    .ForEach(D => 
    {
        string OccpStat = Convert.ToString(D["OccpStat"]);

        if (OccpStat.ToLower().Equals("i"))
            D.SetField("OccpStat", Convert.ToBoolean(1));
        else
            D.SetField("OccpStat", Convert.ToBoolean(0));
    });