Re: Named patterns forbidden in Except?
- To: mathgroup at smc.vnet.net
- Subject: [mg110453] Re: Named patterns forbidden in Except?
- From: David Bailey <dave at removedbailey.co.uk>
- Date: Sat, 19 Jun 2010 07:47:20 -0400 (EDT)
- References: <hvevvo$jpk$1@smc.vnet.net>
On 18/06/10 06:25, cca at gregosetroianos.mat.br wrote:
> Hi,
>
> Consider this:
>
> In[1]:= Cases[{-0.5, 1, -3, 2/5, I}, Except[x_Integer]]
>
> During evaluation of In[1]:= Except::named: Named pattern variables are not
> allowed in the first argument of Except[x_Integer].>>
>
> Out[1]= {}
>
> Why are named patterns not allowed in Except?
>
I guess the point is that you could never use the name - because in your
example, if x took a value, Except would fail to match by definition!
David Bailey
http://www.dbaileyconsultancy.co.uk