Re: selecting from lists
- To: mathgroup at smc.vnet.net
- Subject: [mg6222] Re: [mg6184] selecting from lists
- From: Jens Potschadtke <Jens.Potschadtke at stud.uni-erlangen.de>
- Date: Fri, 28 Feb 1997 03:21:41 -0500
- Organization: Institute for Biomedical Engineering at the FAU Erlangen
- Sender: owner-wri-mathgroup at wolfram.com
Frans Martens wrote:
>
> Murray wrote:
>
> The problem: given an arbitrary list v and a list b of the same
> length, whose entries are all Boolean (True or False), construct a
> function s[v, b] whose result is a list consisting only of those
> entries of v for which the corresponding entries in b are True. For
> example,
>
> v = {3, 82, 7, -12, 5};
> b = {False, True, True, False, False};
> s[v, b]
> {82, 7}
>
[...]
>
> Yes, there is a more direct way! I have added some computations.
>
> t[v_,b_] := Cases[Transpose[{v,b}],{a_,True}:>a]
>
You can also give a try to the solution of the wolfram-folks,
because there exists a predefined function:
<<Statistics`DataManipulation`
BooleanSelect[v,b]
----
Jens Potschadtke
Institute for Biomedical Engineering at the University of Erlangen
(Germany)
mailto:Jens.Potschadtke at stud.uni-erlangen.de
http://www.uni-erlangen.de/~sz0438/