Re: Can't assign value to symbols
- To: mathgroup at smc.vnet.net
- Subject: [mg58420] Re: Can't assign value to symbols
- From: dh <dh at metrohm.ch>
- Date: Sat, 2 Jul 2005 04:06:16 -0400 (EDT)
- References: <da2mpq$93f$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Hi Lee,
"Set" has the Attribute HoldFirst. Therefore, if you say
parameters[[1]] = parameters[[2]]
parameters[[1]] will not be evaluated and you are assigning to the array
and not to a,b,c. If have to tell "Set" to evaluate its first argument by:
Evaluate[parameters[[1]]] = parameters[[2]]
sincerely, Daniel
Lee Newman wrote:
> Hello,
>
> Situation: I have a table that contains parameters and sets of values
> that I want to assign to the parameters for the purposes of running a
> simulation.
> - parameters = {{a,b,c},{1,2,3},{4,5,6},{7,8,9}}
> - want to assign values in a given row to the symbols listed in the
> first row.
> - tried using: MapThread[ #1 = #2 &, {parameters[[1]], parameters[[3]]} ]
> - fails with error "Tag Slot in #1 is Protected"
> - tried adding Unprotect[#1] and a variety of other attemps, but can't
> get it to work.
>
> Anyone know how might accomplish this?
>
> Thanks,
> Lee
>
>