How to check a variable is scalar?

Question

Is there a method to check a variable is scalar type?

scalar variables are those containing an integer, float, double , string or boolean but not array object

thanks

@PaoloTedesco: I guess he wants to know whether a var is elementary or a list(enum, struct) — Daniel Abou Chleih, Oct 10 '13 at 09:22
http://stackoverflow.com/questions/15374038/what-is-the-most-efficient-way-to-check-an-executescalar-result-for-existence — user2864338, Oct 10 '13 at 09:22
scalar variables are those containing an integer, float, double , string or boolean but not array object... — Jasper, Oct 10 '13 at 09:24
Joe, your question is not specific enough. There are many more types of variables than the ones you mention. — reinierpost, Oct 10 '13 at 09:29

score 11 · Accepted Answer · answered Oct 10 '13 at 09:23

It depends on what you mean by "scalar", but Type.IsPrimitive sounds like a good match: it's true for boolean, integer types, floating point types and char.

You can use it as in

var x = /* whatever */
if (x.GetType().IsPrimitive) {
    // ...
}

For a more granular approach you can use Type.GetTypeCode instead:

switch (x.GetType().GetTypeCode()) {
    // put all TypeCodes that you consider scalars here:
    case TypeCode.Boolean:
    case TypeCode.Int16:
    case TypeCode.Int32:
    case TypeCode.Int64:
    case TypeCode.String:
        // scalar type
        break;
    default:
        // not a scalar type
}

@joe: No, but don't take my word for it. Read the documentation. — Jon, Oct 10 '13 at 09:28

ispiro · Answer 2 · 2013-10-10T09:30:25.083

2

I'm not sure this will always work, but it might be enough for your needs:

if (!(YourVarHere is System.Collections.IEnumerable)) { }

Or, for checking a Type:

if(!typeof(YourTypeHere).GetInterfaces().Contains(typeof(System.Collections.IEnumerable))) { }

edited Oct 10 '13 at 09:30

answered Oct 10 '13 at 09:25

ispiro

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Why not just `!(variable is IEnumerable)` ? – nawfal Oct 10 '13 at 09:25
1

@joe IEnumerable is the base interface for all enumerable types. An array is enumerable anyway. See http://stackoverflow.com/questions/4590366/how-to-check-if-a-variable-is-an-ienumerable-of-some-sort – nawfal Oct 10 '13 at 09:27
@nawfal You're correct. I was thinking of a Type, not a variable. Edited now. – ispiro Oct 10 '13 at 09:33
@joe You're welcome. Note that the first option in the answer you accepted will fail for any "scalar" Type you might declare, and most of the .Net "scalar" types such as `Form`. As for the second - you'd have to add checks for every Type you need to check.(This is assuming I understood you correctly - that you're looking to exclude array's, List's, etc.) – ispiro Oct 10 '13 at 09:47

How to check a variable is scalar?

2 Answers2