Re: [Haskell-cafe] round function

I think the function you're looking for is: myRound n places = round (n / fromIntegral factor) * factor where factor = 10 ^ (places - 1) In this case, 10 ^ (places - 1) has integral type (either Int or Integer). I need it to be a fractional type to divide n by it, so I use fromIntegral to convert it. /g On 2/12/06, Chatzianastassiou Achilleas wrote:

Thanks for the anwser Sebastian,

this seems to work, however I am trying to implement something like Main> myfunction 123.456 2 120.0

...

From: Sebastian Sylvan Reply-To: sylvan@student.chalmers.se To: Chatzianastassiou Achilleas CC: haskell-cafe@haskell.org Subject: Re: [Haskell-cafe] round function Date: Sun, 12 Feb 2006 22:23:17 +0100

On 2/12/06, Chatzianastassiou Achilleas wrote:

...

Hi all,

I am trying to implement a function that finds the significant figure of a number to a specified point i.e. 2.55555 3 = 2.556. I have implemented something like:

sig :: (RealFrac a, Integral b) => a -> Int -> a sig x y = round y

However this doesn't work. Moreover at the Prelude when i type round 2.3333 2 i get an error. Any suggestions?

Something like:

myround n s = fromIntegral (round (n * factor)) / factor where factor = fromIntegral (10^s)

Basically scaling it to bring the specified number of digits to the left of the decimal point, then rounding, then scaling back.

/S

-- Sebastian Sylvan +46(0)736-818655 UIN: 44640862

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