[Haskell-cafe] String to Double conversion in Haskell

Bjorn Bringert bjorn at bringert.net
Tue Aug 26 09:01:03 EDT 2008

2008/8/24 Daryoush Mehrtash <dmehrtash at gmail.com>:
> I am trying to convert a string to a float.  It seems that Data.ByteString
> library only supports readInt.    After some googling I came accross a
> possibloe implementation: http://sequence.svcs.cs.pdx.edu/node/373
> My questions are:
> a) is there a standard library implementation of string -> Double and float?
> b) Why is it that the ByteString only supports readInt? Is there a reason
> for it?

Hi Daryoush,

are you really looking for ByteString -> Float conversion, or just
plain String -> Float? The latter is really simple, the function is
called 'read' and is available in the Prelude:

$ ghci
GHCi, version 6.8.3: http://www.haskell.org/ghc/  :? for help
Loading package base ... linking ... done.
Prelude> read "3.14" :: Float


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