Re: ReplaceAll and rules from a list v7.0
- To: mathgroup at smc.vnet.net
- Subject: [mg104261] Re: [mg104227] ReplaceAll and rules from a list v7.0
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Sun, 25 Oct 2009 01:08:05 -0400 (EDT)
- Reply-to: hanlonr at cox.net
l = {{1, 1}, {2, 2}, {3, 3}};
Total /@ l
{2,4,6}
Plus @@@ l
{2,4,6}
Plus @@ # & /@ l
{2,4,6}
#[[1]] + #[[2]] & /@ l
{2,4,6}
f[a_, b_] := a + b
f @@@ l
{2,4,6}
a + b /. Thread[{a, b} -> #] & /@ l
{2,4,6}
eqn = x == a + b;
eqn[[2]] /. Thread[{a, b} -> #] & /@ l
{2,4,6}
eqn[[2]] /. Thread /@ (Variables[eqn[[2]]] -> # & /@ l)
{2,4,6}
Bob Hanlon
---- kristoph <kristophs.post at web.de> wrote:
=============
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