Re: [Haskell-beginners] where do i get wrong

isLower takes a character. You need to look at operating on the string with higher order functions which will call isLower on each character. On Mar 2, 2014 2:25 PM, "Roelof Wobben" wrote:

Found this one:

This is partly working:

import Data.Char

x = "aBCde".isLower -- Note that comments are preceded by two hyphens {- or enclosed in curly brace/hypens pairs. -} main = print x

But now I see this error:

- Main.hs@3:5-3:12 Couldn't match expected type `b0 -> c0' with actual type `[Char]' In the first argument of `(.)', namely `"aBCde"' In the expression: "aBCde" . isLower In an equation for `x': x = "aBCde" . isLower - In an equation for `x': x = "aBCde" . isLower

Roelof

Roelof Wobben schreef op 2-3-2014 20:10:

Thanks,

isLower is in base package. The tutorial has not spoken about importing modules.

I use the IDE of fpcomplete.

Roelof

Bob Ippolito schreef op 2-3-2014 20:02:

isLower is not in the Prelude (the automatically imported module built-in functions). Here's the list of all functions in Prelude: http://hackage.haskell.org/package/base/docs/Prelude.html

isLower is in another module. You can figure that out by searching for "isLower" on Hoogle: http://www.haskell.org/hoogle/

You can even find it by searching for it by type, which is useful if you don't remember the precise name. Try searching for "Char -> Bool".

In other words, you'll need to import isLower from somewhere before you can use it.

On Sun, Mar 2, 2014 at 10:45 AM, Roelof Wobben wrote:

...

Hello,

I try to selfstudy haskell by following the yet another haskell tutorial.

Now I have the exercise where I have a string and have to convert it into a list of Booleans based on lower cats letter using map.

So i tried this

x = "aBCde".islower:[]

But I see this error : Not in Scope: 'isLower'.

Where do I make my error.

Do not give the answer otherwise I do not learn anything from it.

Roelof

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