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PORuby 1.9 CSV: selectively ignoring conversions for a column
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  1. PORuby 1.9 CSV: selectively ignoring conversions for a column
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    copied!<p>I have following CSV data:</p> <pre><code>10,11,12.34 </code></pre> <p>I can parse this using CSV from the standard library, and have the values converted from strings to numbers:</p> <pre><code>require 'csv' CSV.parse( "10,11,12.34" ) =&gt; [["10", "11", "12.34"]] CSV.parse( "10,11,12.34", {:converters =&gt; [:integer,:integer,:float]} ) =&gt; [[10, 11, 12.34]] </code></pre> <p>I <em>don't</em> want to convert column 1, I'd just like that left as a string. My guess was I could omit a value from the converters array, but that didn't work:</p> <pre><code>CSV.parse( "10,11,12.34", {:converters =&gt; [nil,:integer,:float]} ) NoMethodError: undefined method `arity' for nil:NilClass from /home/ian/.rvm/rubies/jruby-1.6.6/lib/ruby/1.9/csv.rb:2188:in `convert_fields' from org/jruby/RubyArray.java:1614:in `each' from /home/ian/.rvm/rubies/jruby-1.6.6/lib/ruby/1.9/csv.rb:2187:in `convert_fields' from org/jruby/RubyArray.java:2332:in `collect' from org/jruby/RubyEnumerator.java:190:in `each' from org/jruby/RubyEnumerator.java:404:in `with_index' from /home/ian/.rvm/rubies/jruby-1.6.6/lib/ruby/1.9/csv.rb:2186:in `convert_fields' from /home/ian/.rvm/rubies/jruby-1.6.6/lib/ruby/1.9/csv.rb:1923:in `shift' from org/jruby/RubyKernel.java:1408:in `loop' from /home/ian/.rvm/rubies/jruby-1.6.6/lib/ruby/1.9/csv.rb:1825:in `shift' from /home/ian/.rvm/rubies/jruby-1.6.6/lib/ruby/1.9/csv.rb:1767:in `each' from org/jruby/RubyEnumerable.java:391:in `to_a' from /home/ian/.rvm/rubies/jruby-1.6.6/lib/ruby/1.9/csv.rb:1778:in `read' from /home/ian/.rvm/rubies/jruby-1.6.6/lib/ruby/1.9/csv.rb:1365:in `parse' from (irb):25:in `evaluate' </code></pre> <p>In fact I haven't been able to find any way of specifying that I'd like the first column to be left unconverted. Any suggestions?</p> <hr> <p><strong>Update</strong></p> <p>I think I misunderstood the design intention for <code>:converters</code>. It's not a 1:1 mapping by column, but a list of converters to be applied (I think) to all values. I'm not sure, the docs aren't too clear. So the more general question is: How do I convert some columns in my CSV, and not others?</p>
 

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