String search algorithms
I'm a bit puzzled to find no sub-string search in the Haskell libraries (unless there's some neat composition of the existing Data.List functions that I've missed). Google doesn't help much either. I've found a KMP implementation: http://haskell.org/hawiki/RunTimeCompilation I'm after something that'll report the position of the first occurrence, like Java's String.indexOf(). Alistair. ----------------------------------------- ***************************************************************** Confidentiality Note: The information contained in this message, and any attachments, may contain confidential and/or privileged material. It is intended solely for the person(s) or entity to which it is addressed. Any review, retransmission, dissemination, or taking of any action in reliance upon this information by persons or entities other than the intended recipient(s) is prohibited. If you received this in error, please contact the sender and delete the material from any computer. *****************************************************************
On Mon, 25 Apr 2005, Bayley, Alistair wrote:
I'm a bit puzzled to find no sub-string search in the Haskell libraries (unless there's some neat composition of the existing Data.List functions that I've missed). Google doesn't help much either. I've found a KMP implementation: http://haskell.org/hawiki/RunTimeCompilation
I'm after something that'll report the position of the first occurrence, like Java's String.indexOf().
List.findIndex (List.isPrefixOf "bla") (List.tails "dfvbdbblaesre")
On Mon, 25 Apr 2005, Henning Thielemann wrote:
On Mon, 25 Apr 2005, Bayley, Alistair wrote:
I'm a bit puzzled to find no sub-string search in the Haskell libraries (unless there's some neat composition of the existing Data.List functions that I've missed). Google doesn't help much either. I've found a KMP implementation: http://haskell.org/hawiki/RunTimeCompilation
I'm after something that'll report the position of the first occurrence, like Java's String.indexOf().
List.findIndex (List.isPrefixOf "bla") (List.tails "dfvbdbblaesre")
But I'm curious if you really need the index. Working with indexes on lists is quite inefficient. E.g. if you want to replace substrings you may want to use this implementation: replace :: forall a. (Eq a) => [a] -> [a] -> [a] -> [a] replace src dst = foldr (\x xs -> let y=x:xs in if isPrefixOf src y then dst ++ drop (length src) y else y) [] Prelude Data.List> replace "ocu" "orcu" "hocuspocus" "horcusporcus"
participants (2)
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Bayley, Alistair -
Henning Thielemann