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IntroductionThe standard .NET Framework offers quite a few generic functions to manipulate arrays, however there are some functionalities where extra code will be needed such as appending to the array, removing an element from the array, or removing all elements that fall under a condition. BackgroundYou should have some basic knowledge of generic classes, lists, arrays, etc. The
However, these functionalities by themselves sometimes do not get the job done. This is why I've extended the functionalities a bit more. Using the CodeBasically the code is very simple and gets the job done. class ArrayEx {
/// <summary>
/// Appends a list of elements to the end of an array
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="array"></param>
/// <param name="items"></param>
public static void Append<T>(ref T[] array, params T[] items)
{
int oldLength = array.Length;
//make room for new items
Array.Resize<T>(ref array, oldLength + items.Length);
for(int i=0;i<items.Length;i++)
array[oldLength + i] = items[i];
}
/// <summary>
/// Remove an Array at a specific Location
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="index">index to remove at</param>
/// <param name="list">The Array Object</param>
public static void RemoveAt<T>(int index, ref T[] list)
{
//pre:
if (index < 0 || list == null | list.Length == 0) return;
//move everything from the index on to the left one then remove last empty
if (list.Length > index + 1)
for (int i = index + 1; i < list.Length; i++)
list[i - 1] = list[i];
Array.Resize<T>(ref list, list.Length - 1);
}
///
///<summary> Thanks to homer.
/// Remove all elements in an array satisfying a predicate
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="list">The Array Object</param>
/// <param name="condition">A Predicate when the element shall get removed under.
/// </param>
/// <returns>Number of elements removed</returns>
public static int RemoveAll<T>(ref T[] list, Predicate<T> condition)
{
if (null == condition || null == list || 0 == list.Length) return 0;
int length = list.Length;
int destinationIndex = 0;
T[] destinationArray = new T[length];
for (int i = 0; i < list.Length; i++)
{
if (!condition(list[i]))
{
destinationArray[destinationIndex] = list[i];
destinationIndex++;
}
}
if (destinationIndex != length)
{
Array.Resize<T>(ref destinationArray, destinationIndex);
list = destinationArray;
}
return length - destinationIndex;
}
}
First We Have Append<T>public static void Append<T>(ref T[] array, params T[] items)
This function takes any Keep in mind that you do not want to be doing this over and over again since every append will cost performance. However, if utilized correctly, meaning the items being appended only happens at the end of an operation, then this will be fine. Using The Method...string[] strArray = new string[] { "a", "b", "c" };
string[] strArray2 = new string[] { "d", "e", "f" };
// appends d e f to the first array
ArrayEx.Append<string>(ref strArray, strArray2);
// appends one more element
ArrayEx.Append<string>(ref strArray, "g");
Console.Out.Write(string.Join(strArray));
Then We Have RemoveAt<T>public static void RemoveAt<T>(int index, ref T[] list)
This method will remove an element at a specific location like the Using The Method...string[] strArray = new string[] { "a", "b", "c" };
// remove element b
string Element = ArrayEx.RemoveAt<string>(1,ref strArray);
Then We Have RemoveAll<T>public static int RemoveAll<T>(ref T[] list, Predicate<T> condition)
This method will remove all elements from an The function also returns the number of elements removed. You can alter the function to create all the elements removed if you wish. This can then be used in a recursive search to reduce search surface space. Using The Method...// create array from sentence
string[] strArray = "My Name is Yang Yu and I'm the best!".Split(' ');
int RemoveCount = Ordering.RemoveAll<string>(ref strArray, new Predicate<string>(
delegate(string element)
{
// remove all elements with ' in them
return element.Contains("'");
}
));
Points of InterestYou may also want to create an The functionalities provided here do not replace the ones in the wrapper class History
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