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Create elegant code with generic collections and Predicate delegate

Let's review the following code which works with generic collection:

    List<String> urls = new List<String>();    //represents a bunch of urls
    ...
 
    //Remove all urls that don't start with "http://"
    for (int i = urls.Count - 1; i >= 0; i--)
    {
        if (!urls[i].StartsWith("http://", StringComparison.OrdinalIgnoreCase))
        {
            urls.RemoveAt(i);
        }
    }

This works well but we can do a little better using Predicate (Predicate is essentially a delegate that allows us to filter based on a certain criteria). First, we have to define the method to be the predicate to validate that an url don't starts with an "http://". This would be:

    bool IsNonHttp(string url)
    {
        return !url.StartsWith("http://", StringComparison.OrdinalIgnoreCase);
    }

Which is essentially the same as the statement we had above. Separating it into a separate method has a few advantages, practically the ability to reuse the same logic for other uses. Now once we have this predicate removing all urls that don't start with an "http://" would be:

    urls.RemoveAll(IsNonHttp);

You can also write the whole thing in one line if you so choose by using an anonymous delegate this way:

    urls.RemoveAll(delegate(string url) {
        return !url.StartsWith("http://", StringComparison.OrdinalIgnoreCase);
    });

Other methods of List<T> which take a Predicate:

List.Exists - determines whether the List contains elements that match the conditions defined by the specified predicate.
List.Find - searches for an element that matches the conditions defined by the specified predicate, and returns the first occurrence within the entire List.
List.FindAll - retrieves the all the elements that match the conditions defined by the specified predicate.
List.FindIndex - searches for an element that matches the conditions defined by a specified predicate, and returns the zero-based index of the first occurrence within the List or a portion of it.
List.FindLast - searches for an element that matches the conditions defined by the specified predicate, and returns the last occurrence within the entire List.
List.FindLastIndex - searches for an element that matches the conditions defined by a specified predicate, and returns the zero-based index of the last occurrence within the List or a portion of it.
List.TrueForAll - determines whether every element in the List matches the conditions defined by the specified predicate.