CODEWITHSUNDEEP
c#arraysindexof
user18352010
user18352010

Reputation:

How can I find index of the array in C#?

I am trying to find index of an array.

This is probably easy to do, but I havn't been able to find out how.

From a website, I tried to add a findIndex function, but I am getting an error.
How can I find the index?

namespace exmple.Filters
{
    class dnm2
    {
        public static byte[] Shape(byte[] data)
        {
            byte[] shape = new byte[data.Length];
            byte count = 0;

            for (int i = 0; i < data.Length; i++)
            {
                if (data[i] == 0)
                {
                    shape[i] = (data[i]);

                    int index = shape.findIndex(count);
                    int[] a = {1, 2, 3};
                    int index = a.Indexof((int)3);
                    count += 1;

                }
            }

            return shape;
        }

    public static int findIndex<T>(this T[] array, T item)
    {
        EqualityComparer<T> comparer = EqualityComparer<T>.Default;

        for (int i = 0; i < array.Length; i++)
        {
            if (comparer.Equals(array[i], item)) 
            {
                return i;
            }
        }
 
        return -1;
    }
}

Upvotes: 2

Views: 6104

Answers (3)

Thomas Weller
Thomas Weller

Reputation: 59615

Array.IndexOf() gives you the index of an object in an array. Just make sure you use the same data types, i.e. byte here.

This is the full code, tested in .NET 4.5.2

using System;

namespace ConsoleApp2
{
    class Program
    {
        static void Main()
        {
            byte[] data = { 5, 4, 3, 2, 1 };
            Console.WriteLine(Array.IndexOf(data, (byte)2));
            Console.ReadLine();
        }
    }
}

Upvotes: 3

Manish
Manish

Reputation: 1197

Not sure what you are trying to do but I have fixed your code.

namespace Exmple.Filters
{
    public static class DNM
    {
        public static byte[] Shape(byte[] data)
        {
            byte[] shape = new byte[data.Length];
            byte count = 0;

            for (int i = 0; i < data.Length; i++)
            {
                if (data[i] == 0)
                {
                    shape[i] = (data[i]);
                    int index = shape.FindIndex1(count);
                    int[] a = { 1, 2, 3 };
                    int index1 = Array.IndexOf(a, (int)3);
                    count += 1;

                }
            }
            return shape;
        }

        public static int FindIndex1(this byte[] array, byte item)
        {
            EqualityComparer<byte> comparer = EqualityComparer<byte>.Default;
            for (int i = 0; i < array.Length; i++)
            {
                if (comparer.Equals(array[i], item))
                {
                    return i;
                }
            }

            return -1;
        }
    }
}

there were few issues in your code

  1. Naming rule violations
  2. byte[] already has an FindIndex so compiler was getting confused which one to use (I just removed the generic things and changed the name)
  3. array object doesn't have a IndexOf Method, Array class has a method.

Upvotes: 0

Prasad Telkikar
Prasad Telkikar

Reputation: 16079

Alternate way is to use Array.FindIndex(array, predicate)

var zeroBasedIndex = Array.FindIndex(data, x => x == (byte)2);

Upvotes: 0

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