list.Take(100).ToList() vs. list.GetRange(0,100)

Question

List attendees = new List();
foreach ...
// Error: \"There are too many target users in the email address array\"
// for more tha         


        

Answer 1

Here is GetRange implementation:

public List GetRange(int index, int count)
{
    if (index < 0)
    {
        ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.index, ExceptionResource.ArgumentOutOfRange_NeedNonNegNum);
    }
    if (count < 0)
    {
        ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.count, ExceptionResource.ArgumentOutOfRange_NeedNonNegNum);
    }
    if ((this._size - index) < count)
    {
        ThrowHelper.ThrowArgumentException(ExceptionResource.Argument_InvalidOffLen);
    }
    List list = new List(count);
    Array.Copy(this._items, index, list._items, 0, count); // Implemented natively
    list._size = count;
    return list;
}

And this is Take Implementation

public static IEnumerable Take(this IEnumerable source, int count)
{
    if (source == null)
    {
        throw Error.ArgumentNull("source");
    }
    return TakeIterator(source, count);
}

private static IEnumerable TakeIterator(IEnumerable source, int count)
{
    if (count > 0)
    {
        foreach (TSource iteratorVariable0 in source)
        {
            yield return iteratorVariable0;
            if (--count == 0)
            {
                break;
            }
        }
    }
}

Plus ToList that simply does:

public static List ToList(this IEnumerable source)
{
    if (source == null)
    {
        throw Error.ArgumentNull("source");
    }
    return new List(source);
}

And List constructor:

public List(IEnumerable collection)
{
    if (collection == null)
    {
        ThrowHelper.ThrowArgumentNullException(ExceptionArgument.collection);
    }
    ICollection is2 = collection as ICollection;
    if (is2 != null)
    {
        int count = is2.Count;
        if (count == 0)
        {
            this._items = List._emptyArray;
        }
        else
        {
            this._items = new T[count];
            is2.CopyTo(this._items, 0);
            this._size = count;
        }
    }
    else
    {
        this._size = 0;
        this._items = List._emptyArray;
        using (IEnumerator enumerator = collection.GetEnumerator())
        {
            while (enumerator.MoveNext())
            {
                this.Add(enumerator.Current);
            }
        }
    }
}

You can note immediately how much GetRange is cheaper against Take