Re: a list as an option

*To*: mathgroup at smc.vnet.net*Subject*: [mg67206] Re: a list as an option*From*: Bill Rowe <readnewsciv at earthlink.net>*Date*: Sun, 11 Jun 2006 23:08:34 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

On 6/11/06 at 2:16 AM, akane at netvisao.pt (Akane Tendo) wrote: >If I have a function f with options like: >Options[f]=[...,{pars->{a,b,c}}] How can I change just one of 'pars' >options ('a', 'b' or 'c')? >I tried to change, for example, 'a' to 'd' like this: >SetOptions[f,pars[[1]]->d] But it didn't work. I also tried to access >the option: Options[f,pars] And the result is: {} Does anyone know what >am I doing wrong or if it's not possible at all to have a list as an >option? There is no difficulty in having a list as an option. Changing the first element of the list could be done as follows: In[39]:= Options[f] = {pars -> {a, b, c}} Out[39]= {pars -> {a, b, c}} In[40]:= SetOptions[f, pars -> {d, b, c}] Out[40]= {pars -> {d, b, c}} Or if you can't know the length of the list before hand or the values of each of the other elements In[42]:= SetOptions[f, pars -> (pars /. Options[f] /. {x_, y__} -> {g, y})] Out[42]= {pars -> {g, b, c}} In[43]:= Options[f] Out[43]= {pars -> {g, b, c}} -- To reply via email subtract one hundred and four