Is there any way to move items inside an array? For example:
int[] myArray = {1,2,3,4};
2nd element becomes the last:
int[] myArray = {1,3,4,2};
P.S.: No that's not a homework. I can think of at least one solution but it requires rather difficult implementation:
Any other (read - easier) way to do this?
There is no easy way to do it using an array. You'll have to loop through the array shifting every element up to the index that's moving, and then re-insert that element at the end. You could always use a List<int> to do it.
List<int> list = myArray.ToList();
int value = list[1];
list.RemoveAt(1);
list.Add(value);
myArray = list.ToArray();
Use List<int>. Array is not for such movements of all the elements.
Or try to swap the last and the chosen element, it will mess up the order though.
List<int>.ToArray()If the array is always a fixed size then:
myArray = new int[4] { myArray[0], myArray[2], myArray[3], myArray[1] };
But if it is variable in size then it becomes trickier and is best done in a List first
int lastElement = 0;
List<int> newArray = new List<int>();
for ( int index=0; index<myArray.Length; index++)
{
if ( index == 1 ) lastElement = myArray[index];
else newArray.Add(myArray[index]);
}
newArray.Add(lastElement);
myArray = newArray.ToArray();
myArray = new List<int>(myArray.Where((x, i) => (i != 1)))
{ myArray[1] }.ToArray();
For this instance, you can use the XOR swap:
[Test]
public void TestSwap()
{
int[] myArray = { 1, 2, 3, 4 };
Console.WriteLine(string.Join(", ", myArray));
Swap(myArray, 1, 2);
Swap(myArray, 2, 3);
Console.WriteLine(string.Join(", ", myArray));
}
static void Swap(int[] vals, int x, int y)
{
vals[x] = vals[x] ^ vals[y];
vals[y] = vals[y] ^ vals[x];
vals[x] = vals[x] ^ vals[y];
}
