2008/7/22 Dmitri O.Kondratiev <[EMAIL PROTECTED]>:
> On the side: The more I use Haskell - the more I like it ! It helps me think
> about the problem I solve much more clearly then when I use imperative
> language.
If I want to replace a substring in a string, then I would search my
string left to right, looking for any occurrence of the substring. If
I find such an occurrence, I would replace it and continue searching
from immediately after the replacement. This algorithm can be
directly expressed in Haskell. More efficient algorithms do exist.
replaceStr :: String -> String -> String -> String
replaceStr [] old new = []
replaceStr str old new = loop str
where
loop [] = []
loop str =
let (prefix, rest) = splitAt n str
in
if old == prefix -- found an occurrence?
then new ++ loop rest -- yes: replace it
else head str : loop (tail str) -- no: keep looking
n = length old
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