[Proposal] Add == operator with multi check

[DmitrijOkeanij]

For now i need to write

if( mySomeVarable == 5 || mySomeVarable == 12 || mySomeVarable == 101 )

Very usefull will be short syntax

if(  mySomeVarable == 5 or 12 or 101 )

Or something like that to make quick check if variable is on of the choice.

[YairHalberstadt]

To be consistent with +=, *=, ??= etc. x ||= y would have to mean x = x || y so a different operator would be needed.

That being said, if or patterns are added they would solve this problem for constant s: if(mySomeVarable is 5 or 12 or 101)

[DmitrijOkeanij]

Yes.
May be my variant with ||= is not the best.
It can be something else, but want to solve this long expressions and made its more easy.

May be just

mySomeVarable == 5 or 12 or 101

[DmitrijOkeanij]

I rewrite upper text.
Thanks!

[theunrepentantgeek]

Have you considered that this can be achieved (for your specific example) with an extension method?

using System;
using System.Linq;

public static class IntExtensions {
    public static bool EqualsAnyOf(this int value, params int[] values)
        => values.Any(i => i == value);
}

public class Demo 
{
    public void Main(int value)
    {
        if (value.EqualsAnyOf(5, 12, 101)) 
        {
            // elided
        }
    }
}

More generally, you should check out #2850 (Proposed changes for Pattern Matching in C# 9.0 - Draft Specification) as the syntax proposed there will do exactly what you are requesting.

[spydacarnage]

And you can make that a generic method, not just for int, and it covers all bases.

…

On Sun, 10 Nov 2019, 06:42 Bevan Arps, ***@***.***> wrote: Have you considered that this can be achieved <https://sharplab.io/#v2:D4AQTAjAsAUCAMACEEB0AZAlgOwI4G5ZYQBmZCANmTEQElsAXAUQA8GBTbAZ0wHtvEAb1iJRyMiioAjXrwA2iJrgCuAQzlcAgtgCeAeQBmACgYALTF0Q4GiAG7rl7ADSIADqoBOqgLaXrAbQBdOwd2LgBKETFogF4APhC5Ry5UbR0jTER4qyyYxMdwwhgAXyI4CRoAEXZvXkRYYRho0mQAFkQAWVUcDMZ89kimsUbo6MwDRCN7JPZUJTUNNMMjAFYXCDB1+Ahw8Pqh0aEow+iAelPEdjlMABN2G+PR0oPEZ+KgA=> (for your specific example) with an extension method? using System;using System.Linq; public static class IntExtensions { public static bool EqualsAnyOf(this int value, params int[] values) => values.Any(i => i == value); } public class Demo { public void Main(int value) { if (value.EqualsAnyOf(5, 12, 101)) { // elided } } } More generally, you should check out #2850 <#2850> (*Proposed changes for Pattern Matching in C# 9.0 - Draft Specification*) as the syntax proposed there will do exactly what you are requesting. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <https://github.com/dotnet/csharplang/issues/2947?email_source=notifications&email_token=ADIEDQN3HWO4NNOHTWIL7KDQS6ULRA5CNFSM4JLJAVKKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOEDUWVGI#issuecomment-552168089>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ADIEDQNRYDFIAPBU5VTZSK3QS6ULRANCNFSM4JLJAVKA> .

[TonyValenti]

I would really prefer to see an “in” operator that was essentially an alias for “contains”.

If(x in {1, 2, 3} ) {
...
}

[Richiban]

This is likely to be implemented with "and, or, and not patterns" #1350.

if (x is 1 or 2 or 3)
{
    //...
}