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RE: ReplaceAll and rules from a list v7.0

  • To: mathgroup at smc.vnet.net
  • Subject: [mg104271] RE: [mg104227] ReplaceAll and rules from a list v7.0
  • From: "David Park" <djmpark at comcast.net>
  • Date: Sun, 25 Oct 2009 01:09:58 -0400 (EDT)
  • References: <21648869.1256367070497.JavaMail.root@n11>

I don't see why you are trying to do this with an equation and ReplaceAll
instead of a function. Just Map Total onto the list.

list = {{1, 1}, {2, 2}, {3, 3}};

Total /@ list
{2, 4, 6}

Or you could design your own particular function for combining a and b.

add[{a_, b_}] := a + b

add /@ list
{2, 4, 6}



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



From: kristoph [mailto:kristophs.post at web.de] 

Hi,

Suppose I have the equation

x=a+b

and the list

l={{1,1},{2,2},{3,3}}

How can I quickly assign the list to the above equation, that is, I
would like to get the following result

{2,4,6}

The first element of each sub-list should be assigned to a and the
second to b.

Thanks in advance.
Kristoph




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