Remove item from list based on condition

Question

public struct stuff
{
    public int ID;
    public int quan;
}

I want to to remove a product where ID = 1. I'm trying this currently:

prods.Remove(new stuff{ prodID = 1});

and it's not working.

THANKS TO ALL

Answer 1

You can only remove something you have a reference to. So you will have to search the entire list:

stuff r;
foreach(stuff s in prods) {
  if(s.ID == 1) {
      r = s;
      break;
  }
}
prods.Remove(r);

or

for(int i = 0; i < prods.Length; i++) {
    if(prods[i].ID == 1) {
        prods.RemoveAt(i);
        break;
    }
}

Answer 2

Using linq:

prods.Remove( prods.Single( s => s.ID == 1 ) );

Maybe you even want to use SingleOrDefault() and check if the element exists at all ...

EDIT:
Since stuff is a struct, SingleOrDefault() will not return null. But it will return default( stuff ), which will have an ID of 0. When you don't have an ID of 0 for your normal stuff-objects you can query for this ID:

var stuffToRemove = prods.SingleOrDefault( s => s.ID == 1 )
if( stuffToRemove.ID != 0 )
{
    prods.Remove( stuffToRemove );
}

Answer 3

If you have LINQ:

var itemtoremove = prods.Where(item => item.ID == 1).First();
prods.Remove(itemtoremove)

Answer 4

prods.Remove(prods.Single(p=>p.ID == 1));

you can't modify collection in foreach, as Vincent suggests

Answer 5

You could use Linq.

var prod = from p in prods
           where p.ID != 1
           select p;

Answer 6

If your collection type is a List<stuff>, then the best approach is probably the following:

prods.RemoveAll(s => s.ID == 1)

This only does one pass (iteration) over the list, so should be more efficient than other methods.

If your type is more generically an ICollection<T>, it might help to write a short extension method if you care about performance. If not, then you'd probably get away with using LINQ (calling Where or Single).

Answer 7

prods.Remove(prods.Find(x => x.ID == 1));