question
- To: mathgroup at yoda.physics.unc.edu
- Subject: question
- From: "Paul N. Schatz" <pns at fermi.clas.virginia.edu>
- Date: Fri, 16 Oct 92 15:35:24 -0400
Thread[If[{aa>10,bb>10,cc>10},{4,5,6},{7,8,9}]]
out=
{If[aa > 10, 4, 7], If[bb > 10, 5, 8], If[cc > 10, 6, 9]}
(* BUT!! *)
list={aa,bb,cc}
out=
{aa, bb, cc}
list=Thread[list>{10,10,10}]
out=
{aa > 10, bb > 10, cc > 10}
Thread[If[list,{4,5,6},{7,8,9}]]
out=
{If[list, 4, 7], If[list, 5, 8], If[list, 6, 9]}
(* And it doesn't seem to work because I
gave the list a name! *)
(* However *)
Thread[If[Evaluate[list],{4,5,6},{7,8,9}]]
out=
{If[aa > 10, 4, 7], If[bb > 10, 5, 8], If[cc > 10, 6, 9]}
(* And now it works! *)
(* Why does giving the list a name make a difference? *)
--
Paul N. Schatz
Chemistry Department
University of Virginia
McCormick Road
Charlottesville, VA 22901, USA
phone: 804-924-3249
email: pns at virginia.edu