Re: From list to list of arguments

*To*: mathgroup at smc.vnet.net*Subject*: [mg113301] Re: From list to list of arguments*From*: Bill Rowe <readnews at sbcglobal.net>*Date*: Sat, 23 Oct 2010 07:03:37 -0400 (EDT)

On 10/22/10 at 1:36 AM, sam.takoy at yahoo.com (Sam Takoy) wrote: >Suppose I have a list of arrays, say g = {a, b, c} where a, b, and c >are arrays, and I would like to calculate >Outer[Times, a, b, c] >how do I do it? Perhaps Fold[Outer[Times, #1, #2] &, a, {b, c}] It is unclear to me what result you are looking for. >I tried >Apply[Outer[Times,#]&, g], as in Apply[Outer[Times, #] &, {{1}, >{1}}], but that does not yield the right answer. So the question is: >how does one convert a list {a, b, c} into arguments to a function >of variable number of arguments? Use Sequence. For example: In[1]:= f[x_, y_] := x y In[4]:= testList = {2, 4}; f[Sequence @@ testList] Out[5]= 8 of course for this toy example, f@@testList would obviously do the same thing. >An auxiliary question: within the function f[x__] := ... what kind >of object is x? It's not a list, but what is it? It is a sequence of one or more arbitrary things. Look up Sequence in the Documentation Center