Building a list using LINQ from two lists - linq

Question

I have two lists:
List1 = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K' }
List2 = { 'B', 'C', 'D' }
List1 is all the columns in a table and List2 are the columns that make up a foreign or primary key on that same table.
In this example, 'A', 'B', 'C' and 'D' are a primary key of a table. 'B', 'C' and 'D' are a foreign key of the same table. 'G' and 'H' are two columns of a table I don't want to include.
I can't seem to be able to write a LINQ statement that produces this:
List3 = { 'B', 'C', 'D', 'E', 'F', 'I', 'J', 'K' }
List3 is a list of the parameters I want to give to an "UPDATE" stored procedure I am generating. List2 + 'K' will be my "WHERE"; 'E', 'F', 'I' and 'J' will be the columns the procedure will use in the "SET".
Both List1 and List2 will be different every time the LINQ is executed.
All lists are of type List where DbColumn is defined as:
public class DbColumn
{
public string Name { get; set; }
//public bool IsPrimaryKey { get; set; }
//public bool IsForeignKey { get; set; }
public int OrdinalPosition { get; set; }
public string DataType { get; set; }
public int CharMaxLength { get; set; }
public bool AllowNulls { get; set; }
public static DbColumn Create(string name, int ordinal_position, string data_type, int charMaxLength, string is_nullable)
{
DbColumn column = new DbColumn();
column.Name = name;
//column.IsPrimaryKey = isPk;
//column.IsForeignKey = isFk;
column.OrdinalPosition = ordinal_position;
column.DataType = data_type;
column.CharMaxLength = charMaxLength;
if (!String.IsNullOrEmpty(is_nullable))
column.AllowNulls = is_nullable.ToUpper() == "YES" ? true : false;
else
column.AllowNulls = false;
return column;
}
public override string ToString()
{
return Name;
}
}
Columns can be part of DbConstraint and DbTable. DbTable also has DbConstraint as a properties:
public class DbTable
{
public string Name { get; set; }
public string Catalog { get; set; }
public string Schema { get; set; }
public List<DbColumn> Columns { get; set; }
public DbSProc Insert { get; set; }
public DbSProc Update { get; set; }
public DbSProc Delete { get; set; }
public List<DbSProc> ReadProcedures { get; set; }
public List<DbConstraint> Constraints { get; set; }
public static DbTable Create(string name, string catalog, string schema, List<DbColumn> columns)
{
DbTable table = new DbTable();
table.Catalog = catalog;
table.Schema = schema;
table.Name = name;
table.Columns = columns;
table.ReadProcedures = new List<DbSProc>();
return table;
}
public override string ToString()
{
return Name;
}
}
public class DbConstraint
{
public string Name { get; set; }
public bool IsPrimary { get; set; }
public List<DbColumn> Columns { get; set; }
public static DbConstraint Create(string name, bool isPrimary)
{
DbConstraint constraint = new DbConstraint();
constraint.Name = name;
constraint.IsPrimary = isPrimary;
constraint.Columns = new List<DbColumn>();
return constraint;
}
public override string ToString()
{
return Name;
}
}
The goal of the LINQ statement is to select for parameters only those columns that are necessary for the "WHERE" piece (e.g.: a foreign/primary key plus "_VerCol") and those necessary for the "SET" piece (non-primary keys).
You can find the code on CodePlex: https://sqlmeth.codeplex.com.
Can anybody help me please?
Thank you!

Answer 1

I assume you know the characters you want to exclude.
List<char> a = new List<char>() { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K' };
List<char> b = new List<char>() { 'B', 'C', 'D' };
List<char> exclusionList = new List<char> {'A','G', 'H'};
List<char> c = a.Select(x => x).Where(x => !exclusionList.Contains(x)).ToList();