Ruby 標準添付ライブラリの CSV で Windows-31J (Shift_JIS でも良いけど) な CSV を作っていたのだけれども、特定の文字が含まれていると Encoding::UndefinedConversionError になってしまう。 irb(main):011:0> CSV.open(File.join('/var/tmp/hoge.csv'), 'w', encoding: 'Windows-31J') do |csv| irb(main):012:1* csv << %w( d é f ) irb(main):013:1> end Encoding::UndefinedConversionError: U+00E9 from UTF-8 to Windows-31J irb(main):014:0> CSV.open(File.join('/var/tmp/h
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