How to remove negative values from a List<int>?

Question

I'm ending up with a bunch of ints in my List (named "listInts").

That should not surprise anybody.

My problem is I don't want any negative numbers in there, but there is the possibility of having three, specifically -1, -2, and -3.

I can clumsily remove them via:

if (listInts.Contains(-1) {
    int i = listInts.IndexOf(-1);
    listInts.Remove(i);
    // etc.
}

...but I know this exhudes a code smell stenchier than a whole passle of polecats.

What is a better way?

Answer 1

listInts.RemoveAll(t => t < 0)

Answer 2

I would use LINQ:

listInts = listInts.Where(i => i >= 0).ToList();

Depending on how this is going to be used, you could also avoid the ToList() call and not resave the values:

var positiveInts = listInts.Where(i => i >= 0);

This will still let you enumerate as needed.

If you need to change the list in place, List<T>.RemoveAll is actually a more efficient method:

listInts.RemoveAll(i => i < 0);

However, I do not prefer this as it's a method that causes side effects, and tends to be confusing (hence hampering maintenance) if you're using other LINQ extension methods.