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

  • To: mathgroup at smc.vnet.net
  • Subject: [mg124204] Re: take square of the second and third column of a table
  • From: Alexei Boulbitch <Alexei.Boulbitch at iee.lu>
  • Date: Fri, 13 Jan 2012 04:52:33 -0500 (EST)
  • Delivered-to: l-mathgroup@mail-archive0.wolfram.com

Try this:



lst = RandomInteger[{0, 5}, {7, 3}] (* this is a list like yours *)

lst // MatrixForm



Transpose[

  Transpose[lst] /. {x_, y_, z_} -> {x, y^2, z^2}] // MatrixForm



Or this:



g[{x_, y_, z_}] := {x, y^2, z^2};

Map[g, lst] // MatrixForm



Have fun.





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



Alexei BOULBITCH, Dr., habil.

IEE S.A.

ZAE Weiergewan,

11, rue Edmond Reuter,

L-5326 Contern, LUXEMBOURG



Office phone :  +352-2454-2566

Office fax:       +352-2454-3566

mobile phone:  +49 151 52 40 66 44



e-mail: alexei.boulbitch at iee.lu<mailto:alexei.boulbitch at iee.lu>








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