Re: Part
- Subject: [mg2898] Re: [mg2890] Part
- From: nichols at godel.math.cmu.edu (Preston Nichols)
- Date: 9 Jan 1996 04:14:46 -0600
- Approved: usenet@wri.com
- Distribution: local
- Newsgroups: wri.mathgroup
- Organization: Wolfram Research, Inc.
- Sender: mj at wri.com
Hans Steffani wrote:
> w={{1,2,3},{4,5,6},{7,8,9}}
> npos={2,1}
>
> npos is the position of the element I need.
>
> w[[npos]]
>
> does not work, as it returns the second and the first
> line.
Both Dave Wagner[mg2895] and Ross Moore[mg2894] proposed
w[[Sequence @@ npos]]
as a solution, which looks good to me (except for the usual generic
misgivings one might have about using an undocumented command such
as Sequence).
However, my first thought was to use
w[[##]]& @@ npos
which also seems to work (though it looks dangerously like a
cartoon expletive).
Can anyone comment on the difference between these? Are there any
serious reasons to prefer one over the other, or is it just a matter
of taste?
Preston Nichols
Department of Mathematics
Carnegie Mellon University