mjhjmtu

I'm looking for a way to create a command with which Latex can automatically generate a table with a given amount of columns, and automatically fills in the column numbers as headers.

I'm looking for something like this:

newcommandCountBox[1]
 beginflushright
 begintabular*#1
 hline
 multicolumn1c1 #1 \ hline
 #1 \ hline
 endtabular 
 endflushright

Where the following command creates the following table:

CountBox6

And the following command creates the following table:

CountBox3

I seem to get stuck on having to manually input the ampersands into the multicolumn command (have tried loop, while, and expandafter)

Thanks for the help!

Just in case the original code for the 6 column table:

beginflushright
 begintabular*7
 hline
 multicolumn1c1 & 2 & 3 & 4 & 5 & 6 \ hline 
 & & & & & \ hline

 endtabular 
endflushright

With foreach in TikZ:

documentclassarticle 
usepackagetikz
usepackageetoolbox
usetikzlibrary
 positioning,
 shapes.multipart
 
tikzset
 mynode/.style=
 draw,
 rectangle split,
 rectangle split parts=2,
 text centered,
 ,

newcommandCountBox[1]%
 begintikzpicture
 node[mynode] (1) 1;
 ifnumcomp#1=1%
 foreach mynum 
 [evaluate=mynum as myprev using int(mynum-1)] 
 in 2,...,#1
 node[mynode,xshift=-pgflinewidth,anchor=west] (mynum) at (myprev.east) mynum;
 %
 endtikzpicture%
 

begindocument
CountBox1 

CountBox3

CountBox6

CountBox2 
CountBox4
CountBox7 
enddocument

Here is an expl3 implementation. With the help of array and its w column specifier, all columns can be made as wide as the last (with the largest number).

documentclassarticle

usepackagexparse,array

ExplSyntaxOn
NewDocumentCommandCountBoxm
 
 % measure the wider number
 hbox_set:Nn l_tmpa_box #1 
 dim_set:Nn l_tmpa_dim box_wd:N l_tmpa_box 
 % do as many columns as specified
 begintabular*#1
 hline
 % do '<number> &' one less than specified, then add the last number
 int_step_function:nN #1 - 1 __phlemp_countbox_head:n #1 \
 hline
 % generate as many &'s as necessary to fill the second row
 prg_replicate:nn #1 - 1 & \
 hline
 endtabular
 

% auxiliary function for adding the & after the number
cs_new_protected:Nn __phlemp_countbox_head:n #1 & 
ExplSyntaxOff

begindocument

CountBox3 CountBox10

enddocument

The following uses multido to generate the column numbering sequence and blank row. A similar approach to egreg's uses array's w<align><width> to set the column width to the widest element:

documentclassarticle

usepackagemultido,array

newcounterboxCount
newlengthboxCountwd

makeatletter
newcommandCountBox[1]%
 setcounterboxCount0% Reset boxCount
 settowidthboxCountwd#1% Measure widest element
 defCountBoxSeq@gobble%
 defCountBoxSeqPhantom@gobble%
 multidoi=1+1#1%
 xdefCountBoxSeqCountBoxSeq & i%
 xdefCountBoxSeqPhantomCountBoxSeqPhantom &%
 %
 noindent
 begintabular *#1 
 hline
 CountBoxSeq \
 hline
 CountBoxSeqPhantom \
 hline
 endtabular%

makeatother

begindocument

CountBox5

enddocument