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    <p>This is going to be really difficult. Some things that make FasterCSV, well, <em>faster</em>, make this particularly hard. Here's my best suggestion: FasterCSV can wrap an <a href="http://www.ruby-doc.org/core/IO.html" rel="nofollow">IO</a> object. What you <em>could</em> do, then, is to make your own subclass of <code>File</code> (itself a subclass of <code>IO</code>) that "holds onto" the result of the last <a href="http://www.ruby-doc.org/core/IO.html#method-i-gets" rel="nofollow"><code>gets</code></a>. Then when FasterCSV raises an exception you can ask your special <code>File</code> object for the last line. Something like this:</p> <pre><code>class MyFile &lt; File attr_accessor :last_gets @last_gets = '' def gets(*args) line = super @last_gets &lt;&lt; $/ &lt;&lt; line line end end # then... file = MyFile.open(filename, 'r') csv = FasterCSV.new file row = true while row begin break unless row = csv.shift # do things with the good row here... rescue FasterCSV::MalformedCSVError =&gt; e bad_row = file.last_gets # do something with bad_row here... next ensure file.last_gets = '' # nuke the @last_gets "buffer" end end </code></pre> <p>Kinda neat, right? <em>BUT!</em> there are caveats, of course:</p> <ol> <li><p>I'm not sure how much of a performance hit you take when you add an extra step to every <code>gets</code> call. It might be an issue if you need to parse multi-million-line files in a timely fashion.</p></li> <li><p>This <del><strong>fails utterly</strong></del> might or might not fail if your CSV file contains newline characters inside quoted fields. The reason for this is <a href="https://github.com/circle/fastercsv/blob/master/lib/faster_csv.rb#L1565-1570" rel="nofollow">described in the source</a>--basically, if a quoted value contains a newline then <code>shift</code> has to do additional <code>gets</code> calls to get the entire line. There could be a clever way around this limitation but it's not coming to me right now. If you're sure your file doesn't have any newline characters within quoted fields then this shouldn't be a worry for you, though.</p></li> </ol> <p>Your <em>other</em> option would be to read the file using <code>File.gets</code> and pass each line in turn to <a href="http://fastercsv.rubyforge.org/classes/FasterCSV.html#M000017" rel="nofollow"><code>FasterCSV#parse_line</code></a> but I'm pretty sure in so doing you'd squander any performance advantage gained from using FasterCSV.</p>
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    1. POHow can I further process the line of data that causes the Ruby FasterCSV library to throw a MalformedCSVError?
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    1. USJordan Running
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    1. COIndeed, as mentioned, these files may contain quoted newline characters. I can avoid the unescaped quotes errors by using a FasterCSV parameter :quote_char => '|', but this chokes on the newlines...
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    2. CORight you are. I did come up with a partial solution, which I've changed my code to reflect. Instead of having a new `@last_gets` on every `File#gets`, append the last chunk to it every time, then reset it only after a row is successfully retrieved *or* the exception is thrown. No it's still not a complete solution but I hope it gives you an idea or two.
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