How to search for a string sequence in a file a rewrite it???

[Hal Daume III]

Right.  *Recurse* down the list.  Somethign like:

foo orig_str new_str xl@(x:xs)
  | orig_str `isPrefixOf` xl = <something>
  | otherwise                = x : <something>

--
 Hal Daume III                                   | hdaume@isi.edu
 "Arrest this man, he talks in maths."           | www.isi.edu/~hdaume

On Thu, 13 Mar 2003, Alexandre Weffort Thenorio wrote:

> Well the problem is that the string I want to replace will usually be in the
> middle of a line in the text file and then is PrefixOf of no use?? Any other
> suggestion??
> 
> Like the text file will be similar to
> 
> abcdedjkfhlafl
> sajkhlabbbbsf
> akfhjklafjkhfk
> sdfasfsaasffaa
> 
> So I want to replace this bbbb in the middle there with aaaa. I could run
> lines on the file but from there i have no idea. I have got an idea but for
> it to work I need to know if there is a function that I can replace a
> certain Char in a string by another Char by knowing the index of this char??
> 
> Best Regards
> 
> NooK
> ----- Original Message -----
> From: "Hal Daume III" <hdaume@ISI.EDU>
> To: "Alexandre Weffort Thenorio" <alethenorio@home.se>
> Cc: <haskell@haskell.org>
> Sent: Thursday, March 13, 2003 1:05 AM
> Subject: Re: How to search for a string sequence in a file a rewrite it???
> 
> 
> > This is how I would do it:
> >
> > recurse down the input string.  use isPrefixOf to check is the string youw
> > ant to replace is at the head of the string.  if it is, 'drop' the
> > appropriate number of characters and stick the replacement string on the
> > front.  then recurse.
> >
> > this should be about 3 lines of code.
> >
> > --
> >  Hal Daume III                                   | hdaume@isi.edu
> >  "Arrest this man, he talks in maths."           | www.isi.edu/~hdaume
> >
> > On Thu, 13 Mar 2003, Alexandre Weffort Thenorio wrote:
> >
> > > OK Guys. First I would like to say thanks for all the help given before.
> As
> > > I said I am still learning Haskell. My problem is the following:
> > >
> > > I have a text file and somewhere in the file there is string (Let's say
> > > aaaa). So I need to find this exact string and overwrite with another
> string
> > > (Lets say bbbb).
> > >
> > > I have thought a bit and couldn't find any solution, and I believe it is
> a
> > > piece of cake for some of you. Is there a method already implemented in
> > > haskell to do that??
> > > Anyway thanks in advance.
> > >
> > > Best Regards
> > >
> > > NooK
> > >
> > > ----- Original Message -----
> > > From: "Arthur Baars" <arthurb@cs.uu.nl>
> > > To: <haskell@haskell.org>
> > > Cc: "Norman Ramsey" <nr@eecs.harvard.edu>
> > > Sent: Wednesday, March 12, 2003 1:06 AM
> > > Subject: Re: clueless GHCI user wishes to load QuickCheck
> > >
> > >
> > > > QuickCheck is in de "util" package. You can load a package with the
> > > > -package flag:
> > > >
> > > > $ ghci -package util
> > > > Prelude> :browse QuickCheck
> > > > class Arbitrary a where {
> > > >      arbitrary :: Gen a; coarbitrary :: forall b. a -> Gen b -> Gen
> b; }
> > > > arbitrary :: forall a. (Arbitrary a) => Gen a
> > > > ...
> > > > Prelude>:module QuickCheck
> > > >
> > > > Prelude QuickCheck> :info trivial
> > > > -- trivial is a variable
> > > > trivial :: forall a. (Testable a) => Bool -> a -> Property
> > > >
> > > > Hope this helps.
> > > >
> > > > Cheers,
> > > >
> > > > Arthur
> > > >
> > > > On Tuesday, March 11, 2003, at 07:02 PM, Norman Ramsey wrote:
> > > >
> > > > > Can anyone help me figure out how to load QuickCheck into GHCI?
> > > > > QuickCheck is included in my Debian package, but my attempts
> > > > > at loading it are bootless:
> > > > >
> > > > > Prelude> :load QuickCheck
> > > > > can't find module `QuickCheck'
> > > > > Prelude> :load util/QuickCheck
> > > > > can't find module `util/QuickCheck'
> > > > > Prelude> :info
> > > > > syntax: `:i <thing-you-want-info-about>'
> > > > > Prelude> :load util/QuickCheck.hi
> > > > > can't find module `util/QuickCheck.hi'
> > > > > Prelude> :load /usr/lib/ghc-5.02.2/imports/util/QuickCheck.hi
> > > > > can't find module `/usr/lib/ghc-5.02.2/imports/util/QuickCheck.hi'
> > > > > Prelude> :load /usr/lib/ghc-5.02.2/imports/util/QuickCheck
> > > > > can't find module `/usr/lib/ghc-5.02.2/imports/util/QuickCheck'
> > > > > Prelude>
> > > > >
> > > > > Any advice, anyone?
> > > > >
> > > > >
> > > > > Norman
> > > > > _______________________________________________
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