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

Alexandre Weffort Thenorio alethenorio@home.se
Thu, 13 Mar 2003 01:36:00 +0100


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
> > > > _______________________________________________
> > > > Haskell mailing list
> > > > Haskell@haskell.org
> > > > http://www.haskell.org/mailman/listinfo/haskell
> > > >
> > >
> > > _______________________________________________
> > > Haskell mailing list
> > > Haskell@haskell.org
> > > http://www.haskell.org/mailman/listinfo/haskell
> > >
> >
> > _______________________________________________
> > Haskell mailing list
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> >
>
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