C#, decimal.toString(), and how to get rid of trailing zeros

Today I spend A LOT OF time on trying to display a percentage – string representation of a decimal but without trailing zeros, e.g. 15.1% instead of 15.10%.

In the application I already had NumberFormatInfo for displaying monetary values and percentages. An object of that type was defined as follows:

NumberFormatInfo nfi = new NumberFormatInfo();
nfi.PercentDecimalDigits = 2;
// some additional settings for nfi 
// (including monetary and numeric attributes)

Let’s take the following decimals as examples:

decimal d = 0.241534545765;
decimal d2 = 0.241;
decimal d3 = 0.2;

Having nfi I could get a string representation of a decimal as below:

d.toString("P", nfi);		//24.15%
d2.toString("P", nfi);		//24.10%
d3.toString("P", nfi);		//20.00%

As you see nfi was defined so that only two decimal places were displayed, but always, disregarding the fact whether they are zeros or not. I tried to find a member of NumberFormatInfo class, a hint of how to use it for that purpose (including parsing the string as a result of toString with passing nfi – sick!), but unfortunately I failed.

Solution

Only then a friend of mine showed me how to use decimal.toString() without an instance of NumberFormatInfo class.

d.toString("0.##%");		//24.15%
d2.toString("0.##%");		//24.1%
d3.toString("0.##%");		//20%

It’s worth mentioning that weren’t there ‘%’ character in the expression passed to toString method I would first have to multiply the decimals by 100:

(d * 100).toString("0.##");		//24.15%
(d2 * 100).toString("0.##");		//24.1%
(d3 * 100).toString("0.##");		//20%

That’s it… It’s frustrating I couldn’t fix it myself in a couple of minutes. However at the end of the day the problem is solved, which is a good news.

9 Responses to “C#, decimal.toString(), and how to get rid of trailing zeros”

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osten
June 8, 2009 at 14:53

Hey!

Thanks for this, finding good documentation from microsoft about formatting is a pain. Also this does not work for all datatypes, just decimal (and probably float etc), anyway, thanks again.
Olivier de Rivoyre
June 9, 2009 at 13:58

Thanks for this. Now I use this to have a ‘human’ display (do not display the trailing zeros):

decimal d = 12.103000m;
Console.WriteLine(d.ToString(“#.################################”, CultureInfo.InvariantCulture));
///Ouput: 12.103

Anyne have a better solution?
tewux
August 13, 2009 at 8:08

Maybe it’s not better, but works:
public static string ToTrimmedString(this decimal value)
{
return value.ToString().TrimEnd(’0′, CultureInfo.CurrentCulture.NumberFormat.NumberDecimalSeparator[0]);
}
Jarosław Dobrzański
August 13, 2009 at 9:29

I believe my suggestion is safer. Thanks for the tip anyway!
Maik Wiege
September 4, 2009 at 10:19

You should use

value.ToString(“G29″);

this makes exactly what you want. It uses the most compact representation of the Decimal value by removing all trailing zeros, no matter how many non-zero values are in front of them.
Check the explanation of the G (General) specifier for numeric formating at the docs.
xxx
April 21, 2010 at 11:34

Got the same problem today !

There is a hack with double.

decimal d1 = 0.0230000m;
MessageBox.Show(((double)d1).ToString());
Paolo
March 16, 2011 at 11:34

Yes, Microsoft documentation is well hidden:
http://msdn.microsoft.com/en-us/library/0c899ak8%28v=VS.90%29.aspx
Nice tutorial.
rkh
January 21, 2012 at 19:01

thanks so much
Sue
June 8, 2012 at 10:03

Thanks! This saved me a lot of time