ruby--ruby/doc/csv/options/parsing/header_converters.rdoc

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====== Option +header_converters+
Specifies converters to be used in parsing headers.
See {Header Converters}[#class-CSV-label-Header+Converters]
Default value:
CSV::DEFAULT_OPTIONS.fetch(:header_converters) # => nil
Identical in functionality to option {converters}[#class-CSV-label-Option+converters]
except that:
- The converters apply only to the header row.
- The built-in header converters are +:downcase+ and +:symbol+.
This section assumes prior execution of:
str = <<-EOT
Name,Value
foo,0
bar,1
baz,2
EOT
# With no header converter
table = CSV.parse(str, headers: true)
table.headers # => ["Name", "Value"]
The value may be a header converter name
(see {Stored Converters}[#class-CSV-label-Stored+Converters]):
table = CSV.parse(str, headers: true, header_converters: :downcase)
table.headers # => ["name", "value"]
The value may be a converter list
(see {Converter Lists}[#class-CSV-label-Converter+Lists]):
header_converters = [:downcase, :symbol]
table = CSV.parse(str, headers: true, header_converters: header_converters)
table.headers # => [:name, :value]
The value may be a \Proc custom converter
(see {Custom Header Converters}[#class-CSV-label-Custom+Header+Converters]):
upcase_converter = proc {|field| field.upcase }
table = CSV.parse(str, headers: true, header_converters: upcase_converter)
table.headers # => ["NAME", "VALUE"]
See also {Custom Header Converters}[#class-CSV-label-Custom+Header+Converters]