You can also do something like this instead of the case statement (this is using GHCI). Prelude> let exclude = ['a', 'e', 'i', 'o', 'u'] Prelude> let f excl letter | letter `elem` excl = 'x' | otherwise = letter Prelude> map (f exclude) "hello" "hxllx" Rob Ziemba On Sun, Oct 4, 2009 at 9:10 AM, Colin Paul Adams wrote:

...

...

...

...

...

"John" == John Moore writes:

John> Hi, I am now writing a function that replaces vowels with John> the letter x. eg.put in a string "help" and out comes hxlp. John> I tried this:

John> f x = case x of

John> {'a' -> 'x';'e' -> 'x';'i' -> 'x';'o' -> 'x';'u' -> John> 'x';_ -> x}

John> but this wont work on strings, only on the individual John> letters. Any direction would be very welcome.

You need to call

map f "whatever"

where f is your function for replacing a character (as above). -- Colin Adams Preston Lancashire _______________________________________________ Beginners mailing list Beginners@haskell.org http://www.haskell.org/mailman/listinfo/beginners

How about instead: devowelize input | elem input "abcde" = 'x' devowelize input = input Not sure if pattern matching is appropriate here. On Sun, Oct 4, 2009 at 12:14 PM, Michael Snoyman wrote:

Or instead of ['a', 'e', 'i', 'o', 'u'] use "aeiou". However, I think the case statement, while my verbose, is also clearer. But that's purely a style choice.

Michael

On Sun, Oct 4, 2009 at 8:55 PM, Robert Ziemba wrote:

...

You can also do something like this instead of the case statement (this is using GHCI). Prelude> let exclude = ['a', 'e', 'i', 'o', 'u'] Prelude> let f excl letter | letter `elem` excl = 'x' | otherwise = letter Prelude> map (f exclude) "hello" "hxllx" Rob Ziemba On Sun, Oct 4, 2009 at 9:10 AM, Colin Paul Adams wrote:

...

...

...

...

>> "John" == John Moore writes:

   John> Hi, I am now writing a function that replaces vowels with    John> the letter x.  eg.put in a string "help" and out comes hxlp.    John> I tried this:

   John> f x = case x of

   John>       {'a' -> 'x';'e' -> 'x';'i' -> 'x';'o' -> 'x';'u' ->    John> 'x';_ -> x}

   John> but this wont work on strings, only on the individual    John> letters. Any direction would be very welcome.

You need to call

map f "whatever"

where f is your function for replacing a character (as above). -- Colin Adams Preston Lancashire _______________________________________________ Beginners mailing list Beginners@haskell.org http://www.haskell.org/mailman/listinfo/beginners

_______________________________________________ Beginners mailing list Beginners@haskell.org http://www.haskell.org/mailman/listinfo/beginners

_______________________________________________ Beginners mailing list Beginners@haskell.org http://www.haskell.org/mailman/listinfo/beginners

-- Joe Van Dyk http://fixieconsulting.com