Re: arguments/realtime3d

*To*: mathgroup at smc.vnet.net*Subject*: [mg32302] Re: arguments/realtime3d*From*: "daniel" <6.6e-34 at gmx.de>*Date*: Sat, 12 Jan 2002 05:18:12 -0500 (EST)*Organization*: Technical University Berlin, Germany*References*: <a1mbn7$2t4$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Hello, > In[1]:= g[x___?OptionQ] := Print["Number of arguments: ", Length[{x}]] > > In[2]:= g[a -> b, c -> d, e -> f] > Number of arguments: 3 > > Why would one create a function with only optional arguments in the first > place? Do you intend a Null argument to be valid input as well? > Yes, I want the function to accept a null argument. The function is a constructor for a simulation starting set, it returns a list of system parameters. My concern about Length[x] was what occurs if f is called without an argument and x has been defined elsewhere. Is this safe even for older versions of Mathematica? Thanks for your answer Daniel