Re: Difference of numbers in the list

*To*: mathgroup at smc.vnet.net*Subject*: [mg45922] Re: Difference of numbers in the list*From*: Bill Rowe <readnewsciv at earthlink.net>*Date*: Thu, 29 Jan 2004 05:36:49 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

On 1/28/04 at 5:19 AM, mtmtk2003 at yahoo.com (mtmtk) wrote: >I have this table: >Table[{((6.67/10^8)*157.85)/(0.225 - x)^2, (Pi^2/420^2)*x}, {x, 0., >0.007245, 0.001}] >I wanted to plot the difference of each pair but the only solution >I could find was to first have two tables A and B then take A-B and >try to plot that. >A = Table[{((6.67/10^8)*157.85)/(0.225 - x)^2}, {x, 0., 0.007245, >0.001}] >B = Table[{(Pi^2/420^2)*x}, {x, 0, 0.007245, 0.001}] >A - B >{{0.00020797224691358022}, {0.0002097773366920289}, >{0.00021160751897569133}, {0.00021346324689854517}, >{0.00021534498386961064}, {0.0002172532038538137}, >{0.00021918839166184726}, {0.00022115104324936126}} >But ListPlot will give an error for this : >"...is not a list of numbers or pairs of numbers." >When I delete the curly braces around the numbers then ListPlot >works. >But this is too complicated for plotting the difference of two sets >of numbers. >How can this be done simply? Thanks for any help. There are a number of ways this can be solved. First, you could get rid of the curly braces in your definition of A and B. That is defining A = Table[((6.67/10^8)*157.85)/(0.225 - x)^2, {x, 0., 0.007245,0.001}] B = Table[(Pi^2/420^2)*x, {x, 0, 0.007245, 0.001}] Now both A and B will be vectors as will be A-B and ListPlot will not complain. However, to me the simplest is to work directly with the initial table. That is data=Table[{((6.67/10^8)*157.85)/(0.225 - x)^2, (Pi^2/420^2)*x}, {x, 0.,0.007245, 0.001}]; ListPlot[Subtract@@@data]; But using your definition of A and B ListPlot[Flatten[A-B]]; will work just fine. This is nothing more than removing one level of curly braces which you describe as "too complicated". I wonder what you are doing when you "delete the curly braces" that you find "too complicated". -- To reply via email subtract one hundred and four