How to convert numbers to string with optimal number of digits?

[AlejandroZepeda]

Hi.

I am trying to do something that seems quite simply, and I am surprised at how much trouble I am having with this.  I am pretty sure that there is a way to get LabVIEW to do this.

I have an array of numbers (double), and I am using the "Array To Spreadsheet String" function to generate a string that I can write to a file.

The problem I am having is that I want to string to omit unnecessary trailing zeros after the decimal point, but I don't want to limit the precision of numbers that do require it.

For example, if my data is this:

0.02

0.4476

-0.0244570001

I would like for the string that I get to be exactly like what I wrote above.  However, depeding on the format string I use, this is what I get:

format string: %.10f

0.0200000000

0.4476000000

-0.0244570001

<OR>

format string: %f  (this seems to default to 6 digits)

0.020000

0.447600

-0.024457

<OR>

format string: %.4f

0.0200

0.4476

-0.0244 <= all trailing digits for this number have been lost!!

Does someone know what the format string should be to get the string I want (which is this:)

0.02

0.4476

-0.0244570001

Thanks in advance,

Alejandro

[dpacaba · Accepted solution]

Hello Alejandro:

Try %#f

[TCPlomp]

---

AlejandroZepeda wrote:

Hi.

I am trying to do something that seems quite simply,

For example, if my data is this:

0.02

0.4476

-0.0244570001

I would like for the string that I get to be exactly like what I wrote above.  However, depeding on the format string I use, this is what I get:

format string: %.10f

0.0200000000

0.4476000000

-0.0244570001

Does someone know what the format string should be to get the string I want (which is this:)

0.02

0.4476

-0.0244570001

Thanks in advance,

Alejandro

---

Hi Alejandro,

remember that if  you used a %20f formatter you most likely would see a digit appearing in the .4476 value. Your computer is binary, but your display is decimal, there allways will be rounding errors.

Ton

[AlejandroZepeda]

Hello.

Thanks for your responses.

I tried using %#f, but I got the same result as %f.

Then I tried %#.10f, and that worked exactly as I wanted it to.

Thanks a lot for the tip, DonPogi!

Alejandro