Использование базовой функции R aggregate
:
aggregate(value ~ name, dat1, I)
# name value.1 value.2 value.3 value.4
#1 firstName 0.4145 -0.4747 0.0659 -0.5024
#2 secondName -0.8259 0.1669 -0.8962 0.1681
Насколько я понимаю, этот код может решить вашу проблему
private LoginUser validate_login(string user, string pass)
{
db_connection();
MySqlCommand cmd = new MySqlCommand();
cmd.CommandText = "Select * from table2 where username=@user and password=@pass and UserID=@UserID";
cmd.Parameters.AddWithValue("@user", user);
cmd.Parameters.AddWithValue("@pass", pass);
cmd.Connection = connect;
LoginUser usr = null;
MySqlDataReader login = cmd.ExecuteReader();
if (login.Read())
{
usr = new LoginUser();
usr.UserID = login["UserID"].ToString();
usr.valid = true;
}
return usr;
}
private void button1_Click(object sender, EventArgs e)
{
{
string user = usertype.Text;
string pass = password.Text;
if (user == "" || pass == "")
{
MessageBox.Show("Empty Fields Detected ! Please fill up all the fields");
return;
}
var r = validate_login(user, pass); //problem line
if (r != null)
{
if (r.valid)
{
MySqlCommand cmd = new MySqlCommand();
MySqlDataReader reader = cmd.ExecuteReader();
Console.WriteLine(String.Format("{0}", r.UserID));
UserDetails.m_gnUserId = Convert.ToInt32(reader["UserID"]);
}
}
}
}