Convert

public static IEnumerable<TDestination> Convert<TSource, TDestination>(this IEnumerable<TSource> enumerable, Func<TSource, TDestination> converter)
{
 if (enumerable == null)
 {
 return null;
 }

 List<TDestination> items = new List<TDestination>();

 foreach (TSource item in enumerable)
 {
 items.Add(converter(item));
 }

 return items.ToArray();
}

int[] integers = new int[] { 5, 25, 50, 100 };
string[] strings = integers.Convert(i => i.ToString());