Re: Collecting Positive and Negative Terms
- To: mathgroup at smc.vnet.net
- Subject: [mg111801] Re: Collecting Positive and Negative Terms
- From: Michael Knudsen <micknudsen at gmail.com>
- Date: Fri, 13 Aug 2010 07:04:29 -0400 (EDT)
- References: <i3tnsg$s5l$1@smc.vnet.net> <i40eu6$bvq$1@smc.vnet.net>
On Aug 12, 11:29 am, Albert Retey <a... at gmx-topmail.de> wrote:
> If your expr is a sum of products (which is what Expand usually
> creates...), the following should work:
>
> Cases[expr, Times[_?Positive, ___]]
Thanks for trying to provide a really simple solution. I tired it out
on one of my rather complicated expressions, but the output didn't
look correct. I therefore tried a trivial example,
myExpression = a + b - c;
Cases[myExpression, Times[_?Positive, ___]]
but the output is just an empty list
{}
What I was hoping for was
a + b
I'll go through some of the more complicated suggestions today and see
how things pan out.
--
Michael Knudsen