Undefined method `header_row?' for ["A", nil]:Array (NoMethodError)

Ruby
1

Can anyone tell me why I am getting the error ?

require ‘csv’

_output_file_path =
File.expand_path(‘output.csv’,File.dirname(FILE))

hash = { ‘A’ => [ ‘v’, ‘x’, ‘y’ , ‘z’ ] ,
‘B’ => [ ‘m’, ‘n’ , ‘o’ ] ,
‘C’ => [ ‘i’, ‘j’ , ‘k’ , ‘l’, ‘m’, ‘n’ , ‘o’ ]
}

headers = hash.keys
csv_row = CSV::Row.new(headers,[],true)
csv_table = CSV::Table.new(csv_row)

headers.each do |col_name|
csv_table[col_name] = hash[col_name]
end

p csv_table.to_csv

~> /home/kirti/.rvm/rubies/ruby-2.0.0-p0/lib/ruby/2.0.0/csv.rb:726:in

block in []=': undefined methodheader_row?’ for [“A”, nil]:Array
(NoMethodError)

~> from

/home/kirti/.rvm/rubies/ruby-2.0.0-p0/lib/ruby/2.0.0/csv.rb:504:in
`each’

~> from

/home/kirti/.rvm/rubies/ruby-2.0.0-p0/lib/ruby/2.0.0/csv.rb:504:in
`each’

~> from

/home/kirti/.rvm/rubies/ruby-2.0.0-p0/lib/ruby/2.0.0/csv.rb:725:in
`each_with_index’

~> from

/home/kirti/.rvm/rubies/ruby-2.0.0-p0/lib/ruby/2.0.0/csv.rb:725:in `[]=’

~> from -:16:in `block in ’

~> from -:15:in `each’

~> from -:15:in `’

2

I have fixed the error. But csv_table not showing any data .

require ‘csv’

_output_file_path =
File.expand_path(‘output.csv’,File.dirname(FILE))

hash = { ‘A’ => [ ‘v’, ‘x’, ‘y’ , ‘z’ ] ,
‘B’ => [ ‘m’, ‘n’ , ‘o’ ] ,
‘C’ => [ ‘i’, ‘j’ , ‘k’ , ‘l’, ‘m’, ‘n’ , ‘o’ ]
}

headers = hash.keys
csv_row = CSV::Row.new(headers,[],true)
csv_table = CSV::Table.new([csv_row])

headers.each do |col_name|
csv_table[col_name] = hash[col_name]
end
csv_table.to_csv

=> “A,B,C\n”

What wrong I did here ?

3

Dear Arup,

Look at

“Columns are returned as an Array of values. Altering that Array has
no effect on the table.”

headers.each do |col_name|
p csv_table[col_name].class # Add this line
csv_table[col_name] = hash[col_name]
end

And you will see:
Array
Array
Array

Abinoam Jr.

4

Abinoam Jr. wrote in post #1137892:

Dear Arup,

Look at
Class: CSV::Table (Ruby 2.1.0)

“Columns are returned as an Array of values. Altering that Array has
no effect on the table.”

But I am using the method #[]=
(Class: CSV::Table (Ruby 2.1.0)
) not #[].

In the default mixed mode, this method assigns rows for index access
and columns for header access.

5

Abinoam Jr. wrote in post #1137892:

Dear Arup,

Look at
Class: CSV::Table (Ruby 2.1.0)

“Columns are returned as an Array of values. Altering that Array has
no effect on the table.”

But I am using the method #[]=
(Class: CSV::Table (Ruby 2.1.0)
) not #[].

In the default mixed mode, this method assigns rows for index access
and columns for header access.