Unit for "Amount of times"

[selmaohneh]

Is your feature request related to a problem? Please describe.
I have a property of type IQuantity that users of my framework can fill as they desire. Often the value represents a technical number with a corresponding unit.
But sometimes the value should represents a simple count of how often something was done. This quantity would be unit-less although being numerical.
Therefore the users have no way to generate the quantity, since the unit is a required argument of i.e. Quantity.From(...).

Describe the solution you'd like
A QuantityType called "None" would fit my needs. It should contain a single unit called "Times", e.g. [1].

[angularsen]

Can you make do with Ratio or Frequency?

[selmaohneh]

Frequency does not work, since it has a time component in it, i.e. times per second.
Ratio would work, since it is unit-less. Still it is not that intuitive, since a ratio implies a relationship between two numbers.

Temperature.From..., Pressure.From... and similar methods force the user to think about what type of quantity they want to create - that's good API design. It's easy, concise and leads the user to use UnitsNet correctly (pit of success). Telling the user to use Ratio for a "count"/"number of times" is misleading and not self-explaining (e.g. I had to open this issue first :D).

In my opinion the QunatityType "None" with unit "Times" would therefore be a good enhancement, even if just for API purposes.

What do you think?

[angularsen]

You are not the first to ask, and the answer has typically been to use double, Ratio or Frequency.
Is there a particular usecase where having this quantity would be more useful to you than double or Ratio?

Since people keep asking about it, I suppose we could add it.
How about something like this:

• Quantity Amount with units:
  • Count (ideally long, but probably decimal like Information or double like the majority of the quantities use)
  • Thousand
  • Million
  • Billion
  • etc..

Amount.FromMillons(1.5).Count; // 1.5e6
Amount.FromCount(1500).Thousands; // 1.5

Not to be confused with https://github.com/angularsen/UnitsNet/blob/master/Common/UnitDefinitions/AmountOfSubstance.json

Since we don't know what we're counting, I feel decimal may be a safer choice. Although, we already have some issues with supporting both decimal and double for things like nanoFramework (#836) and WRC (#815).

[selmaohneh]

I am taking the self-explanatory API position again:

var numberOfSheep = Amount.FromCount(42);

reads very good. This would not be the case when the word Ratio is somewhere in that line... So I'd say you should go for the new type and unit.

I guess .FromCount is enough. The other creation methods might lead to missusages. C# already has enough syntax sugar for creating big numbers, i.e. 42e6.

Not sure about the type, tho. Count always sounds like an int inside the .NET world. Counts like 2.3 and 4.23 do sound more like they could fit inside Ratio since they actually are one. 🤔

[angularsen]

I agree 1.5 "count" does not make much sense, integers would be more natural there - otherwise use Ratio as you say.

Alternative names:

var amount = Amount.FromUnits(42);
amount.Units; // 42

var amount = Amount.FromSingles(42);
amount.Singles; // 42

var amount = Amount.FromOnes(42);
amount.Ones; // 42

var amount = Amount.FromIndividuals(42);
amount.Individuals; // 42

I would argue to keep units of thousands, millions etc. to benefit from these:

var amount = Amount.FromOnes(4200000);
var amountInMilions = amount.Millions; // 4.2
var millionString = amount.ToUnit(AmountUnit.Million).ToString(); // 4.2 M

// as opposed to
var amountInMilions = amount.Ones / 1e6; // 4.2
var millionString = $"{amount.Ones / 1e6} M"; // 4.2 M

[selmaohneh]

Okay, I see the benifit of the helper methods. 👌

Don't like the alternative names (for the default creator method) tho.

My favorites would be FromValue, FromCount or FromAmount.

[angularsen]

I think I like FromValue and .Value the best. @tmilnthorp @lipchev any thoughts on this suggestion overall?

@selmaohneh If we agree on this, would you be interested in attempting a pull request on this? I'm happy to assist.

[selmaohneh]

I'll come back to you later today. I'll have to talk to my colleague about this. If we decide to go the UnitsNet way, I can work on the PR. We would need that functionality in around 3 weeks then. 🙄 Is that goal realistic?

[angularsen]

Great, yes 6 weeks is plenty.

Detailed steps here:
https://github.com/angularsen/UnitsNet/wiki/Adding-a-New-Unit

It is pretty easy once you understand how the code generation based on the JSON files works, and there are a lot of existing quantities to compare to.

[selmaohneh]

Yep, already read that doc. Just wanted to make sure we won't have huge loose ends shortly before the deadline because we aren't able to get a UnitsNet-PR merged. :D

[selmaohneh]

We decided that switching to UnitsNet is out of scope for our sprint. So right now I won't find the time to start implementing it. Freetime is daughter time currently. 😐😊

[tmilnthorp]

This is really just the need to have double/float/etc in an IQuantity format.

I would call it Scalar or Dimensionless and FromValue/Value does seem to be the best fit.

[angularsen]

No problem @selmaohneh , let us know if you want to continue this.
I like Scalar @tmilnthorp 👍

[stale]

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