Re: List operations
- To: mathgroup at smc.vnet.net
- Subject: [mg25463] Re: [mg25399] List operations
- From: Tomas Garza <tgarza01 at prodigy.net.mx>
- Date: Sun, 1 Oct 2000 02:44:47 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
In[1]:=
listA =
{{2, 8}, {1, 3}, {4, 1}, {3, 5}, {4, 6}, {1, 4}, {1, 5}, {1, 5}, {9, 3},
{6, 7}};
In[2]:=
Select[listA, 3*#[[1]] + #[[2]]^2 == 12 &]
Out[2]=
{{1, 3}}
Tomas Garza
Mexico City
"Matt Herman" <Henayni at hotmail.com> wrote:
> Suppose I have a list of ordered pairs {{a1,b1},{a2,b2},...,{an,bn}}.
> What is an efficient way of pulling out all the pairs such that, if I
do
> an operation on the first element in the list, and another on the
> second, and I sum them, they equal some predetermined constant?
>
> For instance, say 3*listpart[[1]]+listpart[[2]]^2