Equality comparison between multiple variables

Question

I've a situation where I need to check whether multiple variables are having same data such as

var x=1;
var y=1;
var z=1;

I want to check whether x==1 and y==1 z==1 (it may be '1' or some other value). instead of this, is there any short way I can achieve same such as below

if(x==y==z==1)

Is this possible in C#?

Answer 1

if (x == y && y == z && z == 1)

There's no other simpler and more efficient ways.

Answer 2

if (x == y && y == z && z == 1)

is the best you can do, because

y == z evaluates to a boolean and you can't compare x with the result:

x == (y == z)

|    |

int  bool

I would do this:

public bool AllEqual<T>(params T[] values) {
    if(values == null || values.Length == 0)
         return true;
    return values.All(v => v.Equals(values[0]));    
}

// ...

if(AllEqual(x, y, z)) { ... }

Answer 3

KennyTM is correct, there is no other simpler or more efficient way.

However, if you have many variables, you could also build an array of the values and use the IEnumerable.All method to verify they're all 1. More readable, IMO.

if (new[] { v1, v2, v3, v4, v5, v6, v7, v8, v9, v10 }.All(x => x == 1))

Instead of

if(v1 == 1 && v2 == 1 && v3 == 1 && v4 == 1 && v5 == 1 && v6 == 1 && v7 == 1 && v8 == 1 && v9== 1 && v10 == 1)

Answer 4

Actually i don't have to the time to code, but an extension method with linq like this

public bool EqualsToAll<T>(this T element, IEnumerable<T> source)
{
    if(element == null)
        throw new ArgumentNullException(element);

    foreach(var item in source)
    {
        if(!element.Equals(item)
            return false;
    }

    return true;
}

should make it.

Warning: This code was not tested, nor written within an IDE.

Answer 5

Here's a nice little recursive solution that works with all types.

class Program
{
    static void Main(string[] args)
    {
        int x = 4, y = 4, z = 4;
        Console.WriteLine(4.IsEqualToAllIn(x, y, z).ToString());
        //prints True

        string a = "str", b = "str1", c = "str";
        Console.WriteLine("str".IsEqualToAllIn(a, b, c).ToString());
        //prints False
    }
}

public static class MyExtensions
{
    public static bool IsEqualToAllIn<T>(this T valueToCompare, params T[] list)
    {
        bool prevResult = true;
        if (list.Count() > 1)
            prevResult = list[0].IsEqualToAllIn(list.Skip(1).ToArray());
        return (valueToCompare.Equals(list[0])) && prevResult;
    }
}

Answer 6

If you just want to testif x == y == z you can use:

var allEqual = new[] {x, y, z}.Distinct().Count() == 1;

If you want to test if they're all equal to 1, add 1 to the set:

var allEqual1 = new[] {x, y, z, 1}.Distinct().Count() == 1;

or use All as in fencliff's answer.

Answer 7

var x = 1;
var y = 1;
var z = 1;

if (AllEqual(1, x, y, z))    // true
if (AllEqual(2, x, y, z))    // false
if (AllEqual(x, y, z))       // true

var a = 1;
var b = 2;
var c = 3;

if (AllEqual(a, b, c))       // false

// ...

public static bool AllEqual<T>(params T[] values)
{
    if (values == null)
        throw new ArgumentNullException("values");

    if (values.Length < 1)
        throw new ArgumentException("Values cannot be empty.", "values");

    T value = values[0];
    for (int i = 1; i < values.Length; i++)
    {
        if (!value.Equals(values[i]))
            return false;
    }
    return true;
}