From: 5.5@...
Date: 2018-04-07T01:09:36+00:00
Subject: [ruby-core:86473] [Ruby trunk Feature#12839] CSV - Give not nil but empty strings for empty fields

Issue #12839 has been updated by 5.5 (5 5).


Thank you very much for fixing #11126.

But I think that the status of my ticket (#12839) should be not Closed but Rejected.
Because my hope is that the CSV parser gives empty strings for empty fields.

Using converters slows the speed.

~~~
gem "benchmark-ips"
require "benchmark/ips"
require "csv"

csv_text = <<EOT
foo,bar,"",baz
hoge,"",temo,""
roo,goo,por,kosh
EOT

conv = ->(s){ s || "" }

Benchmark.ips 20 do |r|
  r.report "without converter" do
    CSV.parse csv_text
  end

  r.report "with converter" do
    CSV.parse csv_text, converters: conv
  end

  r.compare!
end

# Comparison:
#   without converter:     9968.4 i/s
#      with converter:     8590.4 i/s - 1.16x  slower
~~~

----------------------------------------
Feature #12839: CSV - Give not nil but empty strings for empty fields
https://bugs.ruby-lang.org/issues/12839#change-71411

* Author: 5.5 (5 5)
* Status: Closed
* Priority: Normal
* Assignee: kou (Kouhei Sutou)
* Target version: 
----------------------------------------
The CSV parser gives nil for empty fields.

```rb
require "csv"

CSV.parse(%|,""|) #=> [[nil, ""]]
```

The above behavior maybe be suitable for certain programmers, but I hope to get `[["", ""]]`.

So I had used to write the following code reluctantly till Ruby 2.1:

```rb
require "csv"

CSV.parse(%|,""|, converters: lambda{|v| v || ""})
#=> [["", ""]]
```

It is wasteful, but certainly works for my purpose.

However, because of #11126, the above code does not work from Ruby 2.2.
(Converters are not called for nil)

I merely want an option, which makes the CSV parser give empty strings for empty fields.

Namely,

```rb
require "csv"

CSV.parse(%|,""|, string: true) #=> [["", ""]]
```




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