Re: take square of the second and third column of a table

*To*: mathgroup at smc.vnet.net*Subject*: [mg124186] Re: take square of the second and third column of a table*From*: Murray Eisenberg <murray at math.umass.edu>*Date*: Thu, 12 Jan 2012 04:18:18 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*References*: <201201112220.RAA22144@smc.vnet.net>*Reply-to*: murray at math.umass.edu

You can't really operate upon a "table" in Mathematica, as there is no such object. You want instead to operate upon elements at prescribed positions in sublists of a list. (You may _display_ such a list of lists in Table form.) Here's one quick way, by example: tbl = Partition[RandomInteger[{1, 10}, 12], 3]; tbl /. {x_, y_, z_}:> {x, y^2, z^2} On 1/11/12 5:20 PM, hanciong awesome wrote: > Hello, suppose I have a very long table like this: > > 1 2 3 > 4 5 6 > 7 8 9 > ....... > 2 3 4 > > how can I take square of the 2nd and 3rd column? I always do it by > making a new table. so let's say the above table is A and it has 100 > lines, then I make the new table as the following: > > B=Table[{A[[n]][[1]],A[[n]][[2]]^2,A[[n]][[3]]^2},{n,1,100}] > > But if the length of the table is unknown, this way is impractical. > Could anyone suggests better way? thank you > -- Murray Eisenberg murray at math.umass.edu Mathematics & Statistics Dept. Lederle Graduate Research Tower phone 413 549-1020 (H) University of Massachusetts 413 545-2859 (W) 710 North Pleasant Street fax 413 545-1801 Amherst, MA 01003-9305

**References**:**take square of the second and third column of a table***From:*hanciong awesome <hanciong@gmail.com>