Re: Selecting dynamically from a list
- To: mathgroup at smc.vnet.net
- Subject: [mg84745] Re: Selecting dynamically from a list
- From: John Jowett <John.M.Jowett at gmail.com>
- Date: Fri, 11 Jan 2008 22:14:06 -0500 (EST)
- References: <fm4hcd$6ts$1@smc.vnet.net> <fm4sfb$bv0$1@smc.vnet.net>
Jens, Thanks but this doesn't solve the problem (take a look at
FullForm[mychoice] or InputForm[mychoice] and Length[mychoice] always
evaluates to 1.
I still need to use Setting[] ...
John
On Jan 10, 11:36=A0am, Jens-Peer Kuska <ku... at informatik.uni-leipzig.de>
wrote:
> Hi,
>
> SetAttributes[choosein, HoldFirst]
> choosein[mychoice1_, myl_List] :=
> =A0 Module[{dynch}, dynch = mychoice1 = {};
> =A0 =A0CheckboxBar[mychoice1 = Dynamic@dynch, myl]]
>
> choosein[mychoice, {a, b, c, d, e, f}]
>
> and look what the variable mychoice include ..
>
> Regards
> =A0 =A0Jens
>
>
>
> John Jowett wrote:
> > Hello,
> > =A0 =A0 =A0 =A0While writing this post, I found the solution myself. =A0=
At the
> > risk of making myself look a bit slow, let me communicate it anyway.
> > Conceivably it may help someone else who doesn't find the solution
> > obvious.
>
> > I have an application where, in essence, I would like to visually pick
> > a few values out of a list to make a new list. =A0I can do it at a basic=
> > level with
>
> > mylist = {a, b, c, d, e, f};
>
> > CheckboxBar[Dynamic[mychoice0], mylist]
>
> > which displays a row of check boxes. =A0After picking a couple I find
> > that the variable mychoice0 has simply been assigned a value {a,c,e},
> > for example. =A0I can then go on and calculate other things with it,
> > e.g.,
>
> > Length[mychoice0] =A0 which returns 2.
>
> > So far, so good. =A0Then I try to build on that, by writing a function
> > to pick from an arbitrary list. =A0After some trial and error, I came up=
> > with
>
> > choosein[myl_List] := Module[{mychoice1 = {}},
> > =A0 Print[CheckboxBar[Dynamic@mychoice1, myl]];
> > =A0 Dynamic[mychoice1]]
>
> > and try it out with
>
> > myc = choosein[mylist]
>
> > Sure enough this displays an output corresponding to my choice from
> > the check boxes. =A0 However if I try to do anything else with the
> > variable myc, I quickly find out that it is not what it appears to be
> > and cannot be used in calculations. =A0This was puzzling until I
> > discovered that
>
> > myc1 = Setting[myc]
>
> > will give the list I wanted. =A0However it is NOT possible to
> > incorporate the call to Setting in the definition of the function
> > choosein.
>
> > Can anyone improve on this approach ?
>
> > John Jowett- Hide quoted text -
>
> - Show quoted text -