Is there any difference between `x?.ToString("C")` and `$"{x:C}"`?

Asked Apr 03 '19 at 15:19

Active Apr 03 '19 at 15:34

Viewed 52 times

I'm trying to refactor code and wondering if x?.ToString("C") the same as $"{x:C}"? Thanks!

EDIT: The refactoring is part of changing the behavior of a legacy method named ToCurrencyString. Currently, it's behavior is not the desired default for the whole application but we wouldn't like to change whatever calls it. Hope that makes sense.

EDIT 2: forgot to include that x can be null. Tried it and "${x:C}" converts it to string.Empty when x = null.

edited Apr 03 '19 at 15:34

asked Apr 03 '19 at 15:19

Jan Paolo Go

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If you mean change `ToString()` to string interpolation, it's not worth it and will create an extra FormattableString object. From a semantic point, they are equivalent. As a possible refactoring, it's not worth considering. – Panagiotis Kanavos Apr 03 '19 at 15:21
@CamiloTerevinto Yes I'm trying it out but I might miss something not too obvious. – Jan Paolo Go Apr 03 '19 at 15:22
@PaoloGo why consider such a trivial change in the first place? This isn't exactly refactoring. The code doesn't improve in any way – Panagiotis Kanavos Apr 03 '19 at 15:23
If you are doing so, why don't you comment that you get the same or different output? – Camilo Terevinto Apr 03 '19 at 15:23
@PanagiotisKanavos I'm changing from interpolation to ToString. Thanks for the input! – Jan Paolo Go Apr 03 '19 at 15:23
@PanagiotisKanavos That string interpolation will not allocate a new FormattableString object. It compiles directly to `string.Format("{0:C}", x)` – canton7 Apr 03 '19 at 15:23
@PaoloGo *why* ? What do you expect to gain from this? More readable code? Faster? – Panagiotis Kanavos Apr 03 '19 at 15:24
@canton7 making the change even less useful – Panagiotis Kanavos Apr 03 '19 at 15:24
Please see edit on why the need for refactoring. – Jan Paolo Go Apr 03 '19 at 15:25
@PanagiotisKanavos I don't disagree with your overall argument, just pointing out that it's not *quite* as bad as you say. Although the `string.Format` call does go to the pain of getting a new `StringBuilder` from cache, it probably won't allocate (assuming `x` is a reference type) – canton7 Apr 03 '19 at 15:26

Is there any difference between `x?.ToString("C")` and `$"{x:C}"`?

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