Am I using Lists correctly?

Question

In my page load, am I calling ReturnStuff() once or three times? If I am calling it three times, is there a more efficient way to do this?

protected void Page_Load(object sender, EventArgs e)
{
    string thing1 = ReturnStuff(username,password)[0];
    string thing2 = ReturnStuff(username, password)[1];
    string thing3 = ReturnStuff(username, password)[2];
}

public static List<string> ReturnStuff(string foo, string bar)
{

    // Create a list to contain the attributes
    List<string> Stuff = new List<string>();

    // Some process that determines strings values based on supplied parameters

    Stuff.Add(fn);
    Stuff.Add(ln);
    Stuff.Add(em);

    return Stuff;
}

Are you asking whether you're calling the method three times or not? — Erik Dietrich, Mar 20 '12 at 17:39

Joel Coehoorn · Accepted Answer · 2012-03-20T17:43:49.237

13

You're calling it three times. Here is a more efficient way:

protected void Page_Load(object sender, EventArgs e)
{
    var stuff = ReturnStuff(username,password);
    string thing1 = stuff[0];
    string thing2 = stuff[1];
    string thing3 = stuff[2];
}

But more than that, if you have a first name, last name, and e-mail, I would write a function that returns an object composing a first name, last name, and e-mail:

public class User
{
     public string LastName {get;set;}
     public string FirstName {get;set;}
     public string EMail {get;set;}
}

public static User GetUser(string username, string password)
{ 
    // Some process that determines strings values based on supplied parameters

    return new User() {FirstName=fn, LastName=ln, EMail=em};
}

protected void Page_Load(object sender, EventArgs e)
{
    var user = GetUser(username,password);
}

edited Mar 20 '12 at 17:43

answered Mar 20 '12 at 17:38

Joel Coehoorn

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Wow, that is a lot to wrap my n00b head around, so thank you! – mmcglynn Mar 20 '12 at 17:48
@mmcglynn: You can just concentrate on the part about returning the list once first, then :) – BoltClock Mar 20 '12 at 17:48
@BoltClock. Got it. This is a really good example of a simple class, so that helps me. – mmcglynn Mar 20 '12 at 18:11

squillman · Answer 2 · 2012-03-20T18:04:33.453

1

You're calling it 3 times. Call it once and save the results to a variable, then you can work with that variable.

Try this:

var stuff = ReturnStuff(username,password);
string thing1 = stuff[0];
string thing2 = stuff[1];
string thing3 = stuff[2];

edited Mar 20 '12 at 18:04

answered Mar 20 '12 at 17:39

squillman

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Why are you using variant? any significance here? why not strong types? – Pankaj Mar 20 '12 at 17:44
2

@Pankaj Garg: Erm, "variant"? – BoltClock Mar 20 '12 at 17:47
I use var to reduce the signal to noise ratio in my code. It's not always appropriate, and not even always a good idea. Have a read through this. http://stackoverflow.com/questions/41479/use-of-var-keyword-in-c-sharp – squillman Mar 20 '12 at 17:48
Why did not you prefer dynamic ? – Pankaj Mar 20 '12 at 17:56
I use var instead of dynamic to maintain static typing. I'd rather the compiler catch my screw-ups than the run-time. – squillman Mar 20 '12 at 18:08
@PankajGarg "var" **is** strong-typed, and it's short for "variable", not "variant". "Variant" implies weak typing, where as "var" declared an _inferred_ strongly-typed variable. – Joel Coehoorn Mar 20 '12 at 18:24
Yeah, strong not static... Mistyped that one in my comment. – squillman Mar 20 '12 at 18:26

score 1 · Answer 3 · answered Mar 20 '12 at 17:46

3 times. following code will help you realize. go to Main function and call func() from there.

class howmanytimescallingafunction
     {
        public static int i = 0;
        public List<string> fun()
        {
            List<string> list = new List<string> { "A", "B", "C" };
            i++;
            return list;
        }
        public void func()
        {
            Console.WriteLine(fun()[0]);
            Console.WriteLine(i);
            Console.WriteLine(fun()[1]);
            Console.WriteLine(i);
            Console.WriteLine(fun()[2]);
            Console.WriteLine(i);
        }
    }

You should call that function once, get the returned value in a local List<> variable and then access using the variable. like this:

List<string> list = function-that-returns-List<string>();
list[0]; //Do whatever with list now.

Am I using Lists correctly?

3 Answers3