[erlang-questions] wierd outome on my match method

Hugo Mills <>
Sat Jan 31 15:29:57 CET 2015


On Sat, Jan 31, 2015 at 03:11:57PM +0100, Roelof Wobben wrote:
> Hello,
> 
> I have made this match method :
> 
> match_key( _Key, [] , List) ->
>   List ;
> 
> match_key( Key, [Head | Tail], List ) ->
>   case element(1, Head) of
>     Key -> match_key(Key, Tail, [element(2,Head) | List] );
>     _ -> match_key(Key, Tail,  List )
>    end.
> 
> match( Key, [] ) ->
>   {error, "Instance"};
> 
> match(Key, List) ->
>   delete_key (Key, List, []).

   Is this function really what you mean to do?

   Hugo.

> But when I have this database.
> 
> Db5 :  [{name2,tamara},{name,chantal},{name,roelof}]
> 
> and I do this :
> 
>  Db11 = db:match(name,Db5).
> 
> I see this outcome :
> 
> [{name2,tamara}]
> 
> and when I do this :
> 
>  Db10 = db:match(name2,Db5).
> 
> I see this outcome:
> 
> [{name,roelof},{name,chantal}]
> 
> So it schould be the other way around.
> 
> Can someone help me figure out what went wrong ?
> 
> Roelof
> 
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> 
> http://erlang.org/mailman/listinfo/erlang-questions

-- 
Hugo Mills             | O tempura! O moresushi!
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