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Re: evaluate f[{x,y,z}] when f[x,y,z] defined

  • To: mathgroup at smc.vnet.net
  • Subject: [mg103413] Re: [mg103383] evaluate f[{x,y,z}] when f[x,y,z] defined
  • From: "Kurt TeKolste" <tekolste at fastmail.us>
  • Date: Sun, 20 Sep 2009 06:25:19 -0400 (EDT)
  • References: <200909190926.FAA22303@smc.vnet.net>

In[143]:= f[x_, y_, z_] := Sqrt[x^2 + y^2 + z^2]; a = {4, 3, 2}; f @@ a

Out[143]= Sqrt[29]

Or, equivalently

In[146]:= Apply[f,a]

Out[146]= Sqrt[29]

ekt

On Sat, 19 Sep 2009 05:26 -0400, "Murray Eisenberg"
<murray at math.umass.edu> wrote:
> I ought to know how to do this (simply) but don't, or at least don't 
> recall how...
> 
> Often I have a function of several variables defined, for example:
> 
>    f[x_, y_, z_] := Sqrt[x^2 + y^2 + z^2]
> 
> And I have some list of numbers, e.g.:
> 
>    a = {4, 3, 2};
> 
> How can I evaluate the following...
> 
>    f[a]
> 
> ... without having to make a separate definition such as
> 
>    f[{x_, y_, z_}] := f[x, y,z]
> 
> ?
> 
> -- 
> Murray Eisenberg                     murray at math.umass.edu
> Mathematics & Statistics Dept.
> Lederle Graduate Research Tower      phone 413 549-1020 (H)
> University of Massachusetts                413 545-2859 (W)
> 710 North Pleasant Street            fax   413 545-1801
> Amherst, MA 01003-9305
> 
Regards,
Kurt Tekolste



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