title: Reading CSV data into subscripted set
body: <p>I would like to ask for your assistance with a problem I'm dealing for about a week. I have been looking everywhere for the solution. Official doc is not accurate enough and says nothing on that matter.</p>
  
  <p>The problem is the following:
  This is a part of my CSV file "food.csv". Here I copied only 6 columns only to make a small previe of the data.</p>
  
  <pre><code>Name    Index   A   E   K   C
  Rice    1   0   0   0   0
  Lentils 2   0.39    5   0.05    44
  Carrot  3   167.05  7   132 59
  Potato  4   0.03    0   21  74
  Apple   5   0.38    1   6   0.04
  </code></pre>
  
  <p>I'm importing it into GNU MathProg linear program using <code>table</code> statement. The problem is, for each column I'm forced to use separated parameter. I would prefer to index columns into single two dimensional parameter so that I could iterate over them easily.</p>
  
  <pre><code>set fields;
  param kc{i in 1..card(fields)}, symbolic; # symbolic only for the example, normally it's numeric
  table data IN "CSV" "food.csv": fields &lt;- [Index], kc~Kcal;
  </code></pre>
  
  <p>The problem is this way I have to use separate parameter for each column, if I have like 40 collumns and two constraints for each of those columns, it gives about 80 constraints in separated lines, if I want to change something, I need to change 80 lines of code, because I cannot iterate over columns and simplify it.</p>
  
  <p>Here I put what is parsed from CSV file.</p>
  
  <pre><code>Display statement at line 213
  kc[1] = '1.12'
  kc[2] = '3.53'
  kc[3] = '0.41'
  kc[4] = '0.86'
  kc[5] = '0.48'
  kc[6] = '3.89'
  kc[7] = '0.36'
  kc[8] = '1.89'
  kc[9] = '8.84'
  kc[10] = '0.72'
  kc[11] = '1.2'
  kc[12] = '2.95'
  kc[13] = '6.54'
  kc[14] = '5.41'
  kc[15] = '0.81'
  kc[16] = '1.49'
  kc[17] = '0.4'
  </code></pre>
  
  <p>And what would be more interresting is having something like:</p>
  
  <pre><code>kc[1][1] # first entry, first column
  kc[1][2] # first entry, second column
  kc[2][5] # second entry entry, fifth column
  </code></pre>
  
  <p>Does anyone has an idea how to achieve this?</p>