How to remove zero elements from List<string>?

Question

Read couple of examples, but seems i`m doing something wrong. Need to remove all "0" strings from a HUGE List without using hashtables.

Tryed using lambda samples from Stack Owerflow and MSDN examples, but looks i`m messing something up.

DataTable book = SQL.SqlGetTable(BookList.SelectedItem.ToString());
List<string> pagesExist = new List<string>();
for (int i = 0; i < book.Rows.Count; i++)
{
    pagesExist.Add(book.Rows[i][0].ToString());
}

var found = pagesExist.Find(x => x == "0");
if (found != null) 
    pagesExist.Remove(found);

I have a pagesExist list of 4000 string elements. Supposed that

var found = pagesExist.Find(x => x == "0"); 

will accumulate all zeroes in list and will remove them next string. But somehow found results in 0 elements

Answer 1

No need to create the pagesExist list. Just filter out all non zero rows using a simple linq query over the DataTable. This way your entire code is reduced to only:

DataTable book = SQL.SqlGetTable(BookList.SelectedItem.ToString());
var result = book.AsEnumerable().Where(r => r.Field<int>("FieldName") != 0);

I am assuming that the column contains integers only. If not then keep the use Field<string> and filter for != "0".

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As a side note I would recommend looking into SqlGetTable. If it returns a DataTable it already brings all this data into memory from database, something that can be avoided with using linq directly over the DBMS using tools like linq-2-sql or linq-2-entities