I have a array of int which I have to sort by descending.
Since I did not find any method to sort the array in descending order.Currently I am sorting the array in descending order as below
int[] array = new int[] { 3, 1, 4, 5, 2 };
Array.Sort<int>( array );
Array.Reverse( array );
Now,the question is that.Is there any better way to do the same in c#?
Use LINQ OrderByDescending method. It returns IOrderedIEnumerable<int>, which you can convert back to Array if you need so. Generally, List<>s are more functional then Arrays.
array = array.OrderByDescending(c => c).ToArray();
int from perspective of composite objects (not simple objects), then int it's the same object like others, because either of two objects you need to compare till 1st difference, so O(n) it's impossible result.
OrderBy() is a different algorithm than Array.Sort(). Anyone interested see this post stackoverflow.com/questions/1832684/…Depending on the sort order, you can do this :
int[] array = new int[] { 3, 1, 4, 5, 2 };
Array.Sort<int>(array,
new Comparison<int>(
(i1, i2) => i2.CompareTo(i1)
));
... or this :
int[] array = new int[] { 3, 1, 4, 5, 2 };
Array.Sort<int>(array,
new Comparison<int>(
(i1, i2) => i1.CompareTo(i2)
));
i1 and i2 are just reversed.
- (minus sign) before CompareTo
Array.Sort(array, (a, b) => b.CompareTo(a)) for a reverse sort.
For in-place sorting in descending order:
int[] numbers = { 1, 2, 3 };
Array.Sort(numbers, (a, b) => b.CompareTo(a));
For out-of-place sorting (no changes to input array):
int[] numbers = { 1, 2, 3 };
var sortedNumbers = numbers.OrderByDescending(x => x).ToArray();
Sure, You can customize the sort.
You need to give the Sort() a delegate to a comparison method which it will use to sort.
Using an anonymous method:
Array.Sort<int>( array,
delegate(int a, int b)
{
return b - a; //Normal compare is a-b
});
Read more about it:
Yes, you can pass predicate to sort. That would be your reverse implementation.
You may specify a comparer(IComparer implementation) as a parameter in Array.Sort, the order of sorting actually depends on comparer. The default comparer is used in ascending sorting
class Program
{
private static int[] table;
static void Main(string[] args)
{
int[] ints = new int[] { 6, 2, 5, 99, 55 };
table = ints.OrderByDescending(x => x).ToArray();
foreach (var item in table)
{
Console.WriteLine(item);
}
}
