title: Proper way to deal with empty numeric cells in a CSV file
body: <p>I am reading in a CSV file from a commercial measurement processing software by writing my own CSV import method (in c# btw). The contents are a bit strange in that many intermittent empty cells occur where there should be numeric values. Like so:</p>
  <blockquote>
  <p>Zeit [s] ; Speed [m/s] ; Distance [m] ; X [m/s²] ; Y [m/s²] ; Z [m/s²] ; Zext [m/s²] ;</p>
  <p>0,100000 ; 0,000000 ; 0,000000 ; 0,004023 ; 0,009220 ; -0,007959 ; 0,035353 ;</p>
  <p>0,100167 ;  ;  ;  ;  ;  ; -0,021732 ;</p>
  <p>0,100333 ;  ;  ;  ;  ;  ; -0,003706 ;</p>
  <p>0,100500 ;  ;  ;  ;  ;  ; 0,041362 ;</p>
  <p>0,100667 ;  ;  ;  ;  ;  ; 0,035353 ;</p>
  <p>0,100833 ;  ;  ;  ;  ;  ; 0,044366 ;</p>
  <p>0,101000 ; 0,000000 ; 0,000000 ; -0,003253 ; 0,000765 ; 0,003821 ; 0,008312 ;</p>
  <p>0,101167 ;  ;  ;  ;  ;  ; -0,006710 ;</p>
  <p>0,101333 ;  ;  ;  ;  ;  ; -0,027741 ;</p>
  <p>and so on...</p>
  </blockquote>
  <p><strong>Is there any convention for CSV that dictates how to deal with the missing values when the respective column is numeric?</strong></p>
  <p>To me it is rather obvious from the specific experimental context that the missing values should be constant (i.e. staying at the last valid value in that column), but when I am writing a general import filter for CSV, I would like to safely assume that this is <strong>always</strong> the case for CSV's from different sources.</p>
  <p>And what about the time column/abscissae: if they were ever missing some values, it makes no sense to keep them constant (and since I don't know for sure that abscissae are always in the first column, I don't know what to keep constant at all!)...</p>
  <p>Otherwise I am asking myself how a commercial package can throw out such an ill-defined rubbish of a CSV file.</p>
  <p><strong>PS:</strong> sorry if the c# tag is wrong, it's just the language I am coding in, but it has no direct relation to the question. Could be removed if not desired.</p>