Btukfyl

How to store a calculated value in array?

zz(1) = ( xx(1) + yy(1) )/2

fpevalzz(counter){(xx(counter)+yy(counter))/2} NOT working

documentclass{beamer}

usepackage{siunitx,amsmath}

usepackage{xparse,xfp}



ExplSyntaxOn

NewDocumentCommand{newarray}{m}

 {

  seq_new:c { l_hafid_array_#1_seq }

  cs_new:cpn { #1 } ##1

   {

    seq_item:cn { l_hafid_array_#1_seq } { ##1 }

   }

 }

NewDocumentCommand{readarray}{mm}

 {

  seq_set_split:cnn { l_hafid_array_#1_seq } { & } { #2 }

 }

cs_generate_variant:Nn seq_set_split:Nnn { c }



NewExpandableDocumentCommand{sumarray}{O{15}m}

 {

  fp_eval:n { round( seq_use:cn { l_hafid_array_#2_seq } { + }, #1 ) }

 }



ExplSyntaxOff



begin{document}



newarray{xx}

readarray{xx}{1&2&3&4&5}



newarray{yy}

readarray{yy}{6&7&8&9&10}



begin{frame}

begin{table}

begin{tabular}{cccc}

No & xx & yy & zz   \ hline

1 & xx{1} & yy{1} &  fpeval{(xx{1}+yy{1})/2}  \

2 & xx{2} & yy{2} &  fpeval{(xx{2}+yy{2})/2}  \

3 & xx{3} & yy{3} &    \

4 & xx{4} & yy{4} &    \

5 & xx{5} & yy{5} &    \ hline

end{tabular}

end{table}

end{frame}



%newarray{zz}

%readarray{xx}{0&0&0&0&0}

newcountcounter

counter=5

loop

fpevalzz(counter){(xx(counter)+yy(counter))/2}

advance counter by -1

unlessifnum counter<1

repeat



end{document}

I did not really try to make your example work but would like to propose an alternative way of doing what I think you want to do.

documentclass{beamer}

usepackage{pgfmath}



begin{document}



defxx{{1,2,3,4,5}}

defyy{{6,7,8,9,10}}



newcommand{Parse}[1]{pgfmathparse{#1}pgfmathresult}



begin{frame}

begin{table}

begin{tabular}{cccc}

No & xx & yy & zz   \ hline

1 & Parse{xx[0]} & Parse{yy[0]} & Parse{xx[0]/2+yy[0]/2}\ 

2 & Parse{xx[1]} & Parse{yy[1]} & Parse{xx[1]/2+yy[1]/2}\ 

3 & Parse{xx[2]} & Parse{yy[2]} & Parse{xx[2]/2+yy[2]/2}\ 

4 & Parse{xx[3]} & Parse{yy[3]} & Parse{xx[3]/2+yy[3]/2}\ 

5 & Parse{xx[4]} & Parse{yy[4]} & Parse{xx[4]/2+yy[4]/2}\ 

hline

end{tabular}

end{table}



newcounter{counter}

setcounter{counter}{4}

loop

Parse{xx[numbervalue{counter}]/2+yy[numbervalue{counter}]/2} 

addtocounter{counter}{-1}

unlessifnumnumbervalue{counter}=-1

repeat

end{frame}

end{document}

Of course you can also store the results in an array. (Note that I am using foreach here which I find easier to deal with.

documentclass{beamer}

usepackage{pgfmath,pgffor}



begin{document}



defxx{{1,2,3,4,5}}

defyy{{6,7,8,9,10}}



newcommand{Parse}[1]{pgfmathparse{#1}pgfmathresult}



begin{frame}

begin{table}

begin{tabular}{cccc}

No & xx & yy & zz   \ hline

1 & Parse{xx[0]} & Parse{yy[0]} & Parse{xx[0]/2+yy[0]/2}\ 

2 & Parse{xx[1]} & Parse{yy[1]} & Parse{xx[1]/2+yy[1]/2}\ 

3 & Parse{xx[2]} & Parse{yy[2]} & Parse{xx[2]/2+yy[2]/2}\ 

4 & Parse{xx[3]} & Parse{yy[3]} & Parse{xx[3]/2+yy[3]/2}\ 

5 & Parse{xx[4]} & Parse{yy[4]} & Parse{xx[4]/2+yy[4]/2}\ 

hline

end{tabular}

end{table}



foreach X in {4,3,...,0}

{%

 pgfmathparse{xx[X]/2+yy[X]/2}

 ifnumX=4

    xdefzz{pgfmathresult}

 else

    xdefzz{zz,pgfmathresult}

 fi     

}

xdefzz{{zz}}

Parse{zz[2]}

end{frame}

end{document}

The listofitems package may give you at least some of what you need in terms of storing arrays.

documentclass{beamer}

usepackage{siunitx,amsmath,xparse,xfp}

usepackage{listofitems}

begin{document}

setsepchar{&}

readlistxx{1&2&3&4&5}

readlistyy{6&7&8&9&10}

begin{frame}[fragile]

begin{table}

begin{tabular}{cccc}

No & xx & yy & zz   \ hline

1 & xx[1] & yy[1] &  fpeval{(xx[1]+yy[1])/2}  \

2 & xx[2] & yy[2] &  fpeval{(xx[2]+yy[2])/2}  \

3 & xx[3] & yy[3] &    \

4 & xx[4] & yy[4] &    \

5 & xx[5] & yy[5] &    \ hline

end{tabular}

end{table}

makeatletter

deftmp{}

foreachitemzinxx{%

  ifnumzcnt=1relaxelseg@addto@macrotmp{&}fi%

  edeftmpA{fpeval{(z+yy[zcnt])/2}}%

  expandafterg@addto@macroexpandaftertmpexpandafter{tmpA}}

makeatother

readlistzz{tmp}

foreachitemzinzz{zz[-zcnt] }

end{frame}

end{document}