## 2017 Problem Authoring Workshop

### Variable-length Tables?

by Barbra Steinhurst -
Number of replies: 2
Okay, so this feels really advanced and complicated, if it is even possible...

I'd like to build a T-table with the first column x-coordinates and the second column y-coordinates. I'd like the first row to be a randomly-generated pair (x1,y1) and the last row to be a randomly-generated pair (x2,y2). I'd like the in-between rows to be x1+1, x1+2, x1+3, etc up to x2. But the number of these rows, as well as the contents therein, vary depending on what x1 and x2 are. I may be totally dreaming that it could be this customizable. But now I've got the curiosity bug to find out.
In reply to Barbra Steinhurst

### Re: Variable-length Tables?

by Barbra Steinhurst -
Hm... is it possible to define an array that starts with variable x1 then counts up by 1's to variable x2? Then use the length_array variable to define the number of rows in the table?
In reply to Barbra Steinhurst

### Re: Variable-length Tables?

by Davide Cervone -
Here is an example that creates a table with rows for each x between two randomly selected values. Perhaps that will be sufficient for you to modify it for your needs:
loadMacros(
"MathObjects.pl",
"PGML.pl",
"niceTables.pl"
);

$x1 = random(-5,5,1);$x2 = random($x1+1,$x1+5,1);

$f = Formula("x/2+1"); # # The first row of the table is headers for the columns # (formatted using LaTeX) # @xy = ([['$$x$$', header=>'CH'], ['$$y$$', header=>'CH']]); # # Add the rows to the table. The values are put between # $$and$$ so they will be formatted as mathematics # for$x ($x1..$x2) {
push(@xy, ['$$'.x.'$$', '$$'.f->eval(x => x).'$$']);
}

#
#  Create the table using DataTable().  The three stars are
#     so that the LaTeX will be formatted after being inserted.
#
BEGIN_PGML
[@ DataTable( [ @xy ], align => "|c|c|", midrules=>1) @]***
END_PGML

Hope that gets you where you need to go.