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/