Re: proper way to manipulate lists?
- To: mathgroup at smc.vnet.net
- Subject: [mg40196] Re: proper way to manipulate lists?
- From: bobhanlon at aol.com (Bob Hanlon)
- Date: Tue, 25 Mar 2003 14:49:00 -0500 (EST)
- References: <b5p158$7sk$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
n=3;
data = Table[ToExpression[#<>ToString[k]& /@ {"x","y"}],{k,1,n}];
data2 = data /. {x_,y_}:>{a*x,b*y}
{{a x1,b y1},{a x2,b y2},{a x3,b y3}}
data3 = {a,b}*#& /@ data
{{a x1,b y1},{a x2,b y2},{a x3,b y3}}
Bob Hanlon
In article <b5p158$7sk$1 at smc.vnet.net>, Nathan Moore <nmoore at physics.umn.edu>
wrote:
<< Subject: proper way to manipulate lists?
From: Nathan Moore <nmoore at physics.umn.edu>
To: mathgroup at smc.vnet.net
Date: Tue, 25 Mar 2003 07:40:24 +0000 (UTC)
I'm sure this is a one-liner, but it has stumped me for years. Suppose
I'm working with a 2-d array of data,
data = {{x1,y1},{x2,y2}...{xN,yN}};
and I want to transform the data according to,
data2 = {{x1*a,y1*b},{x2*a,y2*b}...{xN*a,yN*b}};
The only way I know to do this is to move the data to excel,
performing the transform and then move the data back to Mathematica. This
is crazy - there must be a better way - is there? Please tell me there
is! >><BR><BR>