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Re: Mixing optional parameters and options

• To: mathgroup at smc.vnet.net
• Subject: [mg116172] Re: Mixing optional parameters and options
• From: thomas <thomas.muench at gmail.com>
• Date: Fri, 4 Feb 2011 01:38:13 -0500 (EST)
• References: <iie0bv$bt3$1@smc.vnet.net>

See here for a solution to this problem, provided by Leonid Shifrin:

http://groups.google.com/group/comp.soft-sys.math.mathematica/browse_frm/thread/35ff6cf97d5019ec/df1b14a433eb2fa6?lnk=gst&q=Functions+with+variable+number#df1b14a433eb2fa6

thomas

On Feb 3, 11:34 am, Peter Breitfeld <ph... at t-online.de> wrote:
> To give a simpe example which, I hope, makes clear my issue:
> Suppose I define this (silly) example function:
>
> Options[f]={bla->True};
> f[x_,y_:11,OptionsPattern[]:=If[OptionValue[bla],x*y,y/x]
>
> Now:
> f[5]    ----> 55 (ok)
> f[5,7]  ----> 35 (ok)
>
> f[5,7,bla->False]  ----> 7/5 (ok)
> f[5,bla->False]    ----> 5*(bla->False)
>
> I expected the result 11/5
>
> The only way I found was to define f like this:
>
> f[{x_,y_:11},OptionsPattern[]]
>
> Can it be done without the curly braces?
>
> Thank you
> --
> _________________________________________________________________
> Peter Breitfeld, Bad Saulgau, Germany --http://www.pBreitfeld.de