Re: something nice I found today, return multiple values from a function

*To*: mathgroup at smc.vnet.net*Subject*: [mg113134] Re: something nice I found today, return multiple values from a function*From*: "Nasser M. Abbasi" <nma at 12000.org>*Date*: Wed, 13 Oct 2010 23:29:20 -0400 (EDT)*References*: <i927an$3io$1@smc.vnet.net> <i93kbo$e67$1@smc.vnet.net>*Reply-to*: nma at 12000.org

On 10/12/2010 11:42 PM, Albert Retey wrote: >> > > 1) I think it has been mentioned in another post today: Module with an > empty list is just an elaborate noop: You better just say: > > getPointCoordinates[x_, y_] := {x -> 10, y -> 7} > Ok, but I was just using an example to illustrate the main point of how to package multiple return values neatly. > 2) you also might like this: > > > makepoint[p_Symbol,xx_,yy_]:=(p[x]=xx;p[y]=yy; p); > > makepoint[p,10,7] > > p@x > p@y > > hth, > > albert > Well, after more playing around, I know settled on this 'pattern'. But before I show it, let me be clear what I am trying to do: Sometimes I call a Module[] with some input parameters, and it does some computation, and return back number of results. I used to return the result in a LIST to the caller. Had to make sure I access the return values from the list on return in the same order they are put in. A struct would have solved this. But now I can do this, please let me know what you think of this new way: In[11]:= computeSomething[r_] := Module[{var1 = -99, var2 = 20, result}, result["x"] = var1*r; result["y"] = var2*r; result]; In[12]:= result = computeSomething[30]; x = result["x"] y = result["y"] Out[13]= -2970 Out[14]= 600 ---- define some module to do some work and return many results computeSomething[r_] := Module[{var1 = -99, var2 = 20, result}, result["x"] = var1*r; result["y"] = var2*r; result] ---- now call it with some data to compute something result = computeSomething[30]; --- now result is in a struct-like, I can access the --- result by NAME, which is important x = result["x"] y = result["y"] Out[9]= -2970 Out[10]= 600 --------------------------- Now I think I have what seems like a good struct emulation in Mathematica. unless I found a problem with this 'pattern', I think I will start using it. The above is better than what I used to do which is: ------------------------------ computeSomething[r_] := Module[{var1 = -99, var2 = 20, result}, result = {var1*r, var2*r} ]; result = computeSomething[30]; x = result[[1]] y = result[[2]] Out[7]= -2970 Out[8]= 600 ------------------------------------- The difference is that now I do not have to worry about which position each individual result is at. Instead of result[[1]], I write result["x"] Thanks all for the input. --Nasser