Re: Set::setps problems
- To: mathgroup at smc.vnet.net
- Subject: [mg90281] Re: [mg90251] Set::setps problems
- From: DrMajorBob <drmajorbob at att.net>
- Date: Fri, 4 Jul 2008 03:58:51 -0400 (EDT)
- References: <15860788.1215088335161.JavaMail.root@m08>
- Reply-to: drmajorbob at longhorns.com
Nonsense here without a definition for "step", but after supplying one, no
problem:
step = Pi/10;
T = Table[{s, 0}, {s, -Pi, Pi, step}];
For[i = 1, i <= Length[UU], i += 1, UU[[i]][[2]] += 5];
The loop didn't do anything, of course, since
Length@UU
0
Perhaps you meant:
step=Pi/10;
T=Table[{s,0},{s,-Pi,Pi,step}];
For[i=1,i<=Length[T],i+=1,T[[i]][[2]]=T[[i]][[2]]+5];
Set::setps: T[[i]] in the part assignment is not a symbol. >>
Set::setps: T[[i]] in the part assignment is not a symbol. >>
Set::setps: T[[i]] in the part assignment is not a symbol. >>
General::stop: Further output of Set::setps will be suppressed during this
calculation. >>
Looking at an example will show the problem:
T[[3]]
{-((4 \[Pi])/5), 0}
T[[3]][[2]]
0
As the error messages say, 0 is not a symbol, so of course you can't Set
it or add 5 to it.
This works, however:
step = Pi/10;
T = Table[{s, 0}, {s, -Pi, Pi, step}];
For[i = 1, i <= Length@T, i += 1,
T = ReplacePart[T, {i, 2} -> T[[i, 2]] + 5]]
T
{{-\[Pi], 5}, {-((9 \[Pi])/10), 5}, {-((4 \[Pi])/5),
5}, {-((7 \[Pi])/10), 5}, {-((3 \[Pi])/5), 5}, {-(\[Pi]/2),
5}, {-((2 \[Pi])/5), 5}, {-((3 \[Pi])/10), 5}, {-(\[Pi]/5),
5}, {-(\[Pi]/10), 5}, {0, 5}, {\[Pi]/10, 5}, {\[Pi]/5, 5}, {(
3 \[Pi])/10, 5}, {(2 \[Pi])/5, 5}, {\[Pi]/2, 5}, {(3 \[Pi])/5,
5}, {(7 \[Pi])/10, 5}, {(4 \[Pi])/5, 5}, {(9 \[Pi])/10, 5}, {\[Pi],
5}}
or this:
step = Pi/10;
T = Table[{s, 0}, {s, -Pi, Pi, step}];
T += Table[{0, 5}, {s, -Pi, Pi, step}]
{{-\[Pi], 5}, {-((9 \[Pi])/10), 5}, {-((4 \[Pi])/5),
5}, {-((7 \[Pi])/10), 5}, {-((3 \[Pi])/5), 5}, {-(\[Pi]/2),
5}, {-((2 \[Pi])/5), 5}, {-((3 \[Pi])/10), 5}, {-(\[Pi]/5),
5}, {-(\[Pi]/10), 5}, {0, 5}, {\[Pi]/10, 5}, {\[Pi]/5, 5}, {(
3 \[Pi])/10, 5}, {(2 \[Pi])/5, 5}, {\[Pi]/2, 5}, {(3 \[Pi])/5,
5}, {(7 \[Pi])/10, 5}, {(4 \[Pi])/5, 5}, {(9 \[Pi])/10, 5}, {\[Pi],
5}}
Bobby
On Thu, 03 Jul 2008 05:12:58 -0500, Kazimierz Å?akomy
<kazik.lakomy at gmail.com> wrote:
> Hi all,
> I found troubles with such a loop:
>
> T = Table[{s, 0}, {s, -Pi, Pi, step}];
>
> For[i = 1, i <= Length[UU], i += 1,
> UU[[i]][[2]] += 5];
>
> (it's just the example of some general idea of changing values of
> table's elements inside a loop)
>
> And Mathematica returned:
>
> Set::setps: UU[[i]] in the part assignment is not a symbol. >>
> Set::setps: UU[[i]] in the part assignment is not a symbol. >>
> Set::setps: UU[[i]] in the part assignment is not a symbol. >>
> General::stop: Further output of Set::setps will be suppressed during \
> this calculation. >>
>
> I would be very grateful if someone helped me with the issue.
> Thank you in advance.
--
DrMajorBob at longhorns.com