Re: Parts of a list
- To: mathgroup at smc.vnet.net
- Subject: [mg15440] Re: [mg15430] Parts of a list
- From: "C. Frey" <Clemens.Frey at uni-bayreuth.de>
- Date: Mon, 18 Jan 1999 04:21:44 -0500
- Sender: owner-wri-mathgroup at wolfram.com
Hallo,
for this task you can use both Select and Cases; in the latter case you
have to use a conditional pattern. Just look at the following examples:
x={{1,0},{2.5, .5},{3,0},{0,2}};
Then use
Select[x,#[[2]]!=0&]
or
Cases[x,{_,y_}/;y!=0]
Hope that helped
Clemens
------------------------------------------------------------
Clemens Frey
Doctoral Fellow at the
Department of Mathematics/BITOEK
University of Bayreuth(Germany)
clemens.frey at uni-bayreuth.de
http://www.bitoek.uni-bayreuth.de/~Clemens.Frey
------------------------------------------------------------
On Wed, 13 Jan 1999, Hossein Kazemi wrote:
> I have a list (matrix) that looks like this
>
> x={{1,0},{2.5, .5},{3,0},{0,2}}
>
> Now I want to eliminate those vectors that have zero for the second
> case. That is, I want to get
>
> {{2.5, .5},{0,2}}.
>
> Is there a quick way of doing this?
> I tried to apply Select to this but could not get it to work.
>
> Thanks for your help.
>
> Hossein Kazemi
> UMass
> kazemi at som.umass.edu
>
>
>
>