c double to string format

The following examples show how to format float numbers to string in C#. You can use static method String.Format or instance methods double.ToString and float.ToString.

Digits after decimal point

This example formats double to string with fixed number of decimal places. For two decimal places use pattern „0.00“. If a float number has less decimal places, the rest digits on the right will be zeroes. If it has more decimal places, the number will be rounded.

Next example formats double to string with floating number of decimal places. E.g. for maximal two decimal places use pattern „0.##“.

Digits before decimal point

If you want a float number to have any minimal number of digits before decimal point use N-times zero before decimal point. E.g. pattern „00.0“ formats a float number to string with at least two digits before decimal point and one digit after that.

Thousands separator

To format double to string with use of thousands separator use zero and comma separator before an usual float formatting pattern, e.g. pattern „0,0.0“ formats the number to use thousands separators and to have one decimal place.

Float numbers between zero and one can be formatted in two ways, with or without leading zero before decimal point. To format number without a leading zero use # before point. For example „#.0“ formats number to have one decimal place and zero to N digits before decimal point (e.g. „.5“ or „123.5“).

Following code shows how can be formatted a zero (of double type).

Align numbers with spaces

To align float number to the right use comma „,“ option before the colon. Type comma followed by a number of spaces, e.g. „0,10:0.0“ (this can be used only in String.Format method, not in double.ToString method). To align numbers to the left use negative number of spaces.

Custom formatting for negative numbers and zero

If you need to use custom format for negative float numbers or zero, use semicolon separator „;“ to split pattern to three sections. The first section formats positive numbers, the second section formats negative numbers and the third section formats zero. If you omit the last section, zero will be formatted using the first section.

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Friday, June 26, 2009

C# Double Decimal Place using String Format

String Format for Double [C#]

The following examples show how to format float numbers to string in C#. You can use static method String.Format or instance methods double.ToString and float.ToString.

Digits after decimal point

This example formats double to string with fixed number of decimal places. For two decimal places use pattern „0.00“. If a float number has less decimal places, the rest digits on the right will be zeroes. If it has more decimal places, the number will be rounded.

Next example formats double to string with floating number of decimal places. E.g. for maximal two decimal places use pattern „0.##“.

Digits before decimal point

If you want a float number to have any minimal number of digits before decimal point use N-times zero before decimal point. E.g. pattern „00.0“ formats a float number to string with at least two digits before decimal point and one digit after that.

Thousands separator

To format double to string with use of thousands separator use zero and comma separator before an usual float formatting pattern, e.g. pattern „0,0.0“ formats the number to use thousands separators and to have one decimal place.

Float numbers between zero and one can be formatted in two ways, with or without leading zero before decimal point. To format number without a leading zero use # before point. For example „#.0“ formats number to have one decimal place and zero to N digits before decimal point (e.g. „.5“ or „123.5“).

Following code shows how can be formatted a zero (of double type).

Align numbers with spaces

To align float number to the right use comma „,“ option before the colon. Type comma followed by a number of spaces, e.g. „0,10:0.0“ (this can be used only in String.Format method, not in double.ToString method). To align numbers to the left use negative number of spaces.

Custom formatting for negative numbers and zero

If you need to use custom format for negative float numbers or zero, use semicolon separator „;“ to split pattern to three sections. The first section formats positive numbers, the second section formats negative numbers and the third section formats zero. If you omit the last section, zero will be formatted using the first section.

How do I format a Double to a String in C# so as to have only two decimal places?

If I use String.Format(«<0:0.00>%», myDoubleValue) the number is then rounded and I want a simple truncate without any rounding. I also want the conversion to String to be culture sensitive.

15 Answers 15

I use the following:

If the number is 50.947563 and you use the following, the following will happen:

And there’s your answer truncated, now to format the string simply do the following:

The following rounds the numbers, but only shows up to 2 decimal places (removing any trailing zeros), thanks to .## .

I suggest you truncate first, and then format:

Use the constant 100 for 2 digits truncate; use a 1 followed by as many zeros as digits after the decimal point you would like. Use the culture name you need to adjust the formatting result.

Simplest method, use numeric format strings:

i use price.ToString(«0.00») for getting the leading 0s

The c# function, as expressed by Kyle Rozendo:

This is working for me

How about adding one extra decimal that is to be rounded and then discarded:

I know this is a old thread but I’ve just had to do this. While the other approaches here work, I wanted an easy way to be able to affect a lot of calls to string.format . So adding the Math.Truncate to all the calls to wasn’t really a good option. Also as some of the formatting is stored in a database, it made it even worse.

Thus, I made a custom format provider which would allow me to add truncation to the formatting string, eg:

The implementation is pretty simple and is easily extendible to other requirements.

To what is worth, for showing currency, you can use «C» :

You could also write your own IFormatProvider, though I suppose eventually you’d have to think of a way to do the actual truncation.

The .NET Framework also supports custom formatting. This typically involves the creation of a formatting class that implements both IFormatProvider and ICustomFormatter. (msdn)

At least it would be easily reusable.

There is an article about how to implement your own IFormatProvider/ICustomFormatter here at CodeProject. In this case, «extending» an existing numeric format might be the best bet. It doesn’t look too hard.