Declaring a variable inside or outside an foreach loop: which is faster/better?

Question

Which one of these is the faster/better one?

This one:

List list = new List();
User u;

foreach (string s in l)
{
    u = new         


        

Answer 1

A declaration does not cause any code to be executed, so it's not a performance issue.

The second one is what you mean, and you're less likely to make a stupid error if you do it the second way, so use that. Always try to declare variables in the smallest scope necessary.

And besides, the better way is to use Linq:

List users = l.Select(name => new User{ Name = name }).ToList();