Re: get a, b from numbers in the form a+b Pi
- To: mathgroup at smc.vnet.net
- Subject: [mg119160] Re: get a, b from numbers in the form a+b Pi
- From: "Nasser M. Abbasi" <nma at 12000.org>
- Date: Mon, 23 May 2011 06:26:55 -0400 (EDT)
- References: <iraq88$ls8$1@smc.vnet.net>
- Reply-to: nma at 12000.org
On 5/22/2011 3:58 AM, 1.156 wrote:
> I have lists of numbers (Mathematica output) all numerically in the
> form a + b*Pi and I'm trying to extract the values of a and b for
> further work.
>
> Here's an example of the best I've been able to do so far:
>
> nums={1/2 (-2+\[Pi]),-2+(3 \[Pi])/4,-(11/3)+(5 \[Pi])/4,5/48 (-64+21
> \[Pi]),-(61/5)+(63 \[Pi])/16,-(338/15)+(231 \[Pi])/32};
> {FullForm[#][[1,1]],FullForm[#][[1,2]]/\[Pi]}&/@nums
>
> When I run this line of code 4 of the six input numbers give me the
> {a,b} I'm looking for but the first and fourth entries fail because the
> form isn't right. Possibly I could patch this scheme to look for a small
> finite set of possibilities of input number form but I suspect I may a
> long way from attacking this problem correctly.
>
> Can someone offer some other ideas on how to pull this off? Many thanks
> for looking at this. Rob
If you want to use your FullForm method, can't you then just
Expand first?
as in
FullForm[#][[1, 1]], FullForm[#][[1, 2]]/\[Pi]} & /@ Expand[nums]
{{-1,1/2},{-2,3/4},{-(11/3),5/4},{-(20/3),35/16},
{-(61/5),63/16},{-(338/15),231/32}}
It seems to have worked now on all of them.
--Nasser