How to find if a value is in an array in Visual C#

Question

If I have an array of ints, and I want to quickly check if a certain int value is in that array, is there a method to do that?

Answer 1

Enumerable.Contains if you're using C# 3.0 or later.

e.g.

var contained = myArray.Contains(4);

Answer 2

var myArray = new []  { 1, 2};
if myArray.Contains(1)
{
do something
}

You may need a using System.Linq;

Kindness,

Dan

Answer 3

Use for example this, if you want to check if your array contains the int 0:

if (your_int_array.Contains(0))
{
    //Code
}

Answer 4

You could use the IndexOf method:

int[] array = new int[] { 1, 2, 3 };
bool isArrayContains17 = Array.IndexOf(array, 17) > -1;

Answer 5

Try this function:

public static bool FindValueFromArray(object[] Values,object valueToSearch){
    bool retVal = false;
    Array myArray = (Array)Values;
    int found = Array.BinarySearch(myArray, valueToSearch);
    if (found != -1){
        retVal = true;
    }
    return retVal;
}

Hope this helps.

Answer 6

The Enumerable.Contains() Method is your friend in .NET-Framework 3.5...

Answer 7

If the array is sorted, then this is quickest:

Array.BinarySearch(myArray, value) >= 0;

If the array is searched a lot and rarely modified, then you may find it worthwhile to sort the array after modification (using Array.Sort) and use the above. Otherwise, use the option you prefer:

Array.IndexOf(myArray, value) >= 0; //.Net 1

Array.Exists(array, delegate(int x) { return x == value; }); //.Net 2

myArray.Contains(value); //.Net 3

IndexOf has the best performance for unsorted arrays. The second option uses a predicate delegate, and the third requires the creation of an enumerator object.