CSV.filter(input, output, headers: true) does not write the header row to output! about csv

[kou]

Could you open a PR for it?

[kou]

Could you add out_write_headers: true option?

[jeropaul]

No dice on that one, results in the header row being sent to the block, which results in the following:

irb(main):006> CSV.filter(input, output, headers: true, out_write_headers: true) { |row| row['Date and Time'] = "#{row['Date and Time']}+HUH"}
(irb):6:in `[]': no implicit conversion of String into Integer (TypeError)

CSV.filter(input, output, headers: true, out_write_headers: true) { |row| row['Date and Time'] = "#{row['Date and Time']}+HUH"}
                                                                                                        ^^^^^^^^^^^^^^^
	from (irb):6:in `block in <top (required)>'
	from /usr/local/bundle/gems/csv-3.3.0/lib/csv.rb:1231:in `filter'
	from (irb):6:in `<main>'
	from <internal:kernel>:187:in `loop'
	from /usr/local/bundle/gems/irb-1.12.0/exe/irb:9:in `<top (required)>'
	from /usr/local/bundle/bin/irb:25:in `load'
	from /usr/local/bundle/bin/irb:25:in `<top (required)>'
	from /usr/local/bundle/gems/bundler-2.5.7/lib/bundler/cli/exec.rb:58:in `load'
	from /usr/local/bundle/gems/bundler-2.5.7/lib/bundler/cli/exec.rb:58:in `kernel_load'
	from /usr/local/bundle/gems/bundler-2.5.7/lib/bundler/cli/exec.rb:23:in `run'
	from /usr/local/bundle/gems/bundler-2.5.7/lib/bundler/cli.rb:451:in `exec'
	from /usr/local/bundle/gems/bundler-2.5.7/lib/bundler/vendor/thor/lib/thor/command.rb:28:in `run'
	from /usr/local/bundle/gems/bundler-2.5.7/lib/bundler/vendor/thor/lib/thor/invocation.rb:127:in `invoke_command'
	from /usr/local/bundle/gems/bundler-2.5.7/lib/bundler/vendor/thor/lib/thor.rb:527:in `dispatch'
	from /usr/local/bundle/gems/bundler-2.5.7/lib/bundler/cli.rb:34:in `dispatch'
	from /usr/local/bundle/gems/bundler-2.5.7/lib/bundler/vendor/thor/lib/thor/base.rb:584:in `start'
	... 6 levels...

[kou]

The first row is the header and it's an Array:

CSV.filter(input, output, headers: true, out_write_headers: true) { |row| row['Date and Time'] = "#{row['Date and Time']}+HUH" unless row.is_a?(Array)}

[jeropaul]

The first row is the header and it's an Array:

CSV.filter(input, output, headers: true, out_write_headers: true) { |row| row['Date and Time'] = "#{row['Date and Time']}+HUH" unless row.is_a?(Array)}

Okay I've found a unit test that describes this behaviour

The recipe really should be updated https://ruby.github.io/csv/doc/csv/recipes/filtering_rdoc.html#label-Recipe-3A+Filter+String+to+String+with+Headers