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Changing the floating point format in sprintf
f#compiler

I would like to be able to change the precision of floating point numbers written to a string in sprintf. Specifically, rather than say sprintf "%.2f" f, I'd like to be able to change the format, say by using:

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let szformat = sprintf "%.df" 2
let szfloat = sprintf szformat f

The compiler doesn't like it. How can I change the precision?

Thanks, and Happy Holidays to all.

Bob

.

Hi Bob,

I'm not quite sure how I'd do it using the sprintf function in F#, but doing it the C# way (still from F#) is very easy.

let szfloat = f.ToString("f" ^ n.ToString());

Say, if f = 1.2345678, and you call f.ToString("f3"), then you get 1.234, and if you call f.ToString("f4") then you get 1.2345, etc.

^ is the string concatenation operator in F#. You can also use the + operator on strings as well.

Hope that helps,
-Matt

By on 12/26/2007 12:26 PM ()

Hi guys,

You can also use "*" as a specifier in a precision of width field, where an extra integer argument is accepted by the generated format function, e.g.

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printfn "%10.4f" 3.14157

is equivalent to:

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printfn "%*.*f" 10 4 3.14157

Likewise

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printfn "%*d" 3 4

is equivalent to:

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printfn "%3d" 4
By on 12/29/2007 9:18 AM ()

Holy cow! That's awesome!

By on 12/29/2007 9:24 AM ()

Try again :-)

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4

 

printfn "%10.4f" 3.14157

is equivalent to:

1
2
3
4

 

printfn "%*.*f" 10 4 3.14157

Likewise

1
2
3
4

 

printfn "%*d" 3 4

is equivalent to:

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3
4
5

 

printfn "%3d" 4
By on 12/29/2007 11:53 AM ()

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