How to search for a string sequence in a file a rewrite it???
Alexandre Weffort Thenorio
alethenorio@home.se
Thu, 13 Mar 2003 21:13:11 +0100
Ooops a small error before but here is the right one.
Great. I got almost everything. My problem now is:
I got a function called findstr where
findstr "aaaa" "zzzzz" ["xxxxaaaa","xxxaaaaxxx"] =
["xxxxzzzzz","xxxzzzzzxxx"]
and then I try something like
fillIn lines = do
bkfilled <- (findstr str str2 lines)
write bkfilled
where write takes a [String] and concatenates it writing it to a file then.
But I get this error saying:
Expected Type: [String]
Inferred Type: String
In the first argument of 'write' namelly 'bkfilled'
In a do expection pattern binding: write bkfilled
Any idea?? I mean bkfilled is supposed to be [String] but it says it is a
String, any idea why???
Best Regards
Alex
----- 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 1:38 AM
Subject: Re: How to search for a string sequence in a file a rewrite it???
> 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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> > > > > >
> > > > >
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> > > >
> > >
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> > >
> >
>
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