# Help in creating a matrix

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## Help in creating a matrix

 Hi I have dataset with n variables, say n =3  x y z the formula should be form = x+y+z+x*x +x*y+x*z +y*y + y*z+z*z my code has to for  loop Is there any way  to reduce two loops   for (i in 1:n)    {       for (j in i:n)       {         dat= cbind(dat,dat[,i]*dat[,j])       }      } Thanks in Advance         Arun
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## Re: Help in creating a matrix

 >I have dataset with n variables, say n =3  x y z >the formula should be form = x+y+z+x*x +x*y+x*z +y*y + y*z+z*z >my code has to for  loop >Is there any way  to reduce two loops >  for (i in 1:n) >  { >      for (j in i:n) >     { >        dat= cbind(dat,dat[,i]*dat[,j]) >      } >   } Yes; use outer But - Why only two levels of looping for three variables? - What have i, j and dat to do with the formula? - Why doesnt the formula appear anywhere in the loop? ----- Thanks in Advance         Arun -- View this message in context: http://r.789695.n4.nabble.com/Help-in-creating-a-matrix-tp4551532p4551532.htmlSent from the R help mailing list archive at Nabble.com. ______________________________________________ [hidden email] mailing list https://stat.ethz.ch/mailman/listinfo/r-helpPLEASE do read the posting guide http://www.R-project.org/posting-guide.htmland provide commented, minimal, self-contained, reproducible code. ******************************************************************* This email and any attachments are confidential. Any use...{{dropped:8}} ______________________________________________ [hidden email] mailing list https://stat.ethz.ch/mailman/listinfo/r-helpPLEASE do read the posting guide http://www.R-project.org/posting-guide.htmland provide commented, minimal, self-contained, reproducible code.
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## Re: Help in creating a matrix

 The formula is created sepearately and data is created for the formula and then use the modelling lm Thanks in Advance         Arun