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Re: How to map a list on function

  • To: mathgroup at smc.vnet.net
  • Subject: [mg97548] Re: [mg97472] How to map a list on function
  • From: "David Park" <djmpark at comcast.net>
  • Date: Sat, 14 Mar 2009 18:18:40 -0500 (EST)
  • References: <25366638.1237027520702.JavaMail.root@m02>

More like 'map a function onto a list'.

list = {{10, 3, 5, 7}, {4, 6, 8, 9}, {0, 8, 3, 6}};
g[{xexp_, yexp_, zexp_, uexp_}] := x^xexp y^yexp z^zexp u^uexp

Total[g /@ list]
u^6 y^8 z^3 + u^7 x^10 y^3 z^5 + u^9 x^4 y^6 z^8


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


From: buts [mailto:manger31 at yahoo.com] 

Hello,

Could anyone explain me how to do the following:
I have a long list of integer numbers in groups of four:

list= {{10,3,5,7},{4,6,8,9},{0,8,3,6}, ...... }

or its Flatten version.

How to write a fast function g[list] which does this:

g[list] =x^10*y^3*z^5*u^7 + x^4*y^6*z^8*u^9 + y^8*z^3*u^6+ ...

It should be done many times (say, 10^4-6) on lists with length > 1000, so
taking parts is not a good idea.
How to use Map or similar ?
Thanks.




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