title: Ignore errors in pandas astype
body: <p>I have a numeric column that could contain another characters different form <strong>[0-9]</strong>. Say: <code>x = pandas.Series(["1","1.2", "*", "1", "**."])</code>.
  Then I want to <b> convert </b> that serie into a numerical column using <code>x.astype(dtype = float, errors = 'ignore')</code> . I just can't figure out why Pandas keeps giving me an error despite the fact that I ask him not to! Is there something wrong with my code ?</p>