list comprehension

Stephanie Randles Stephanie Randles" <[email protected]
Fri, 19 Oct 2001 19:15:12 +1000


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Hi,=20
I have a script here

interleave :: [Integer] -> [Strings] -> [String]
interleave (x:xs) (y:ys)
        =3D words [a | a <- (unwords [(show x), (filter (/=3D 1) y), =
"+"])]  =20

and the error message i receive is=20

(Instance of Num Char required for definition of interleave)

and I don't understand what this is asking of me.

Please help if you are able to!!!

Thanks.....Steph

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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; =
charset=3Diso-8859-1">
<META content=3D"MSHTML 5.50.4522.1800" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>Hi, </FONT></DIV>
<DIV><FONT face=3DArial size=3D2>I have a script here</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>interleave&nbsp;::&nbsp;[Integer] -&gt; =
[Strings]=20
-&gt; [String]<BR>interleave&nbsp;(x:xs)=20
(y:ys)<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =3D words [a | a =
&lt;-=20
(unwords [(show x), (filter (/=3D 1) y), "+"])]&nbsp;&nbsp; =
</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>and the error message i receive is =
</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>(Instance of Num Char required for =
definition of=20
interleave)</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>and I don't understand what this is =
asking of=20
me.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>Please help if you are able =
to!!!</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial =
size=3D2>Thanks.....Steph</FONT></DIV></BODY></HTML>

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