title: How to read csv file with missing values and 'delim_whitespace=True'?
body: <p>I would like to know if it is possible to simply drop any line that couses error instead of rising an exception.</p>
  
  <p>My issue is connected to processing text file such this one:</p>
  
  <pre>
  111 aaa 222 bbb
  1   a   2   b
  11      22
  </pre>
  
  <p>Because of the varied number of whitespaces as separators, I am using option 'delim_whitespace=True' to read_csv function. I am however also explicitelly specifying data types by 'dtype' parameter.</p>
  
  <p>It is natural that pandas shifts value 22 to second column for the third row (and I don't believe there is a way how to convince it that it actually bellongst to the third one). However since the second column is expected to be string it raises an exception.</p>
  
  <p>I understand that this could be probably solved using 'converters' parameter, but I am worried about performance since the data file is quite large (millions of rows).</p>
  
  <p>So is it possible to drop lines with lower number or columns (there is 'error_bad_lines' for higher) or drop any line which couses exception during retyping. Or do you have any other ideas?</p>