I could access column 2 (Last Name) as either row.field("Last Name") or row.field(1). However, if I tried to access the first column using row.field("First Name"), it would return nil. row.field(0), on the other hand, would return the proper value.

Hmmmm.

After some sleuthing, I examined the raw content of the string:

(rdb:1) p row.headers.first.unpack('C*')
[239, 187, 191, 70, 105, 114, 115, 116, 32, 78, 97, 109, 101]

Ah, ha! The first three characters are the byte-order mark, or BOM. Ruby, for whatever reason, does not strip it when reading a file as input, so it’s passed along in the input stream. When loading a file with FasterCSV, it’ll keep those characters in the key name, causing lookups by the first column key name to return nil.

I modified my file conversion code as follows:

  def convert_to_utf8
    # Data files are exported as Little Endian UTF-16. We need to parse as UTF-8
    contents = File.open(@file_name).read      
    begin
      converted = Iconv.iconv('UTF-8', 'UTF-16LE', contents)
      converted.first.gsub!("\xEF\xBB\xBF", '') # strip the BOM (byte order mark) from the first line of input
      output = File.open(@file_name, 'w')
      output.write(converted)
    rescue Iconv::Failure
      puts $!.inspect
    end
  end

And all is well in the world.