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Re: Map[] and multiple args function

  • To: mathgroup at smc.vnet.net
  • Subject: [mg96228] Re: [mg96198] Map[] and multiple args function
  • From: "David Park" <djmpark at comcast.net>
  • Date: Tue, 10 Feb 2009 05:47:14 -0500 (EST)
  • References: <20738936.1234177212952.JavaMail.root@m02>

You could do something like the following:

Foo[x_, y_, z_] := x + 2*y + 3*z

list = {{1, 2, 3}, {4, 5, 6}};

Total@(Foo @@ # & /@ list)
46

Plus @@ (Foo @@ # & /@ list)
46


David Park
djmpark at comcast.net
http://home.comcast.net/~djmpark/  


From: sagrailo at gmail.com [mailto:sagrailo at gmail.com] 

I know this has to be FAQ, but I'm just not able to find an answer
anywhere, so - here it goes:  I have a multiple-arguments function,
say something like:
   Foo[x_, y_, z_] := x + 2*y + 3*z
Now, I want to call this function number of times, over different sets
of arguments, and then to sum results.  I thought about storing
argument triplets into some kind of list, and then employing sequence
of Map[] and Apply[] to get the job done.  After number of trials and
errors, I came up with following piece of code doing the thing:
  Plus @@ Foo /@ {{1, 2, 3}, {4, 5, 6}} /. List -> Sequence
but I even don't fully understand what's going here, and also I'm
wondering is there a "better" way to accomplish this.  So - any
suggestion?

Thanks.




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