How to create a file name in Ruby with the element of an array?

Question

Say I have an array of some elements, and I want to save the data related to each element in a CSV file. This is my code:

require 'rubygems'
require 'csv'

category_ID = [-1, 0, 1, 2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 15, 17, 18, 19, 20, 21, 91, 92, 93, 94, 101, 102, 103, 104, 105, 106, 107, 111, 112, 113, 114, 115, 116, 117, 118, 119]

CSV.foreach('C:\Users\username\Desktop\Original.csv', :headers=>true) do |row,i|
    category_ID.each {|x|}
        CSV.open('C:\Users\username\Desktop\#{x}.csv', "wb") do |csv|           
            if row[4].gsub(/^[^:]+:\s*/,"") == x
                csv << row[28].gsub(/^[^:]+:\s*/,"")
            end
        end
    end
end

So I want my file names to be -1.csv, 0.csv, 1.csv, ... , 119.csv. But it is giving an error because of the #{x} as the file name. How to correct this? Thanks.

EDIT: This is 1 row from the Original.csv file:

"{""timestamp"""," ""2015-05-10 15",59,"59"""," ""article_category_id"""," ""106"""," ""app_name"""," ""Apple Daily TW"""," ""ip"""," ""111.80.37.218"""," ""app_id"""," ""51ee0d904055aa1539d32523"""," ""datetime"""," ""1431273612198"""," ""edition"""," """""," ""action"""," ""page_view"""," ""article_title"""," ""【溫星母親節】潘若迪竟讓老婆一個人過"""," ""user_id"""," """""," ""menu"""," ""即時新聞"""," ""lon"""," """""," ""platform"""," ""Android"""," ""country_residence"""," """""," ""version"""," ""2.5.2"""," ""page_name"""," ""【溫星母親節】潘若迪竟讓老婆一個人過"""," ""location"""," """""," ""is_registered"""," ""False"""," ""provider"""," """""," ""page_id"""," ""607814"""," ""menu_id"""," ""10002""","  ""article_category"""," ""娛樂"""," ""lat"""," """""," ""article_id"""," ""607814"""," ""country_origin"""," """""," ""udid"""," ""d0155049772de9"""," ""gender"""," """""," ""age"""," """""," ""device"""," ""C6902"""," ""session_id"""," """""," ""push"""," ""N"""," ""os"""," ""4.4.2"""," ""browser"""," """"}",,

shouldn't that be c:\users\username\desktop ? where username is your .. username — peter
– peter, Commented Dec 23, 2016 at 11:52
Yeah, true. I modified the actual path, and in doing so I forgot about the username part. — Kristada673
– Kristada673, Commented Dec 23, 2016 at 11:56
@ShaileshPrajapati Ok, got it. But even after fixing it, its not producing any output file. — Kristada673
– Kristada673, Commented Dec 23, 2016 at 12:02
Could you please show a few lines of your original CSV file? Your code is a bit confusing. — Eric Duminil
– Eric Duminil, Commented Dec 23, 2016 at 12:13

Aleksei Matiushkin · Accepted Answer · 2016-12-23 11:51:59Z

5

This line is a noop:

category_ID.each {|x|}

I guess you wanted to:

category_ID.each do |x|
  CSV.open("C:\Users\Desktop\#{x}.csv", "wb") do |csv|
    if row[4].gsub(/^[^:]+:\s*/,"") == x
      csv << row[28].gsub(/^[^:]+:\s*/,"")
    end
  end
end

edited Dec 23, 2016 at 11:51

answered Dec 23, 2016 at 11:42

Aleksei Matiushkin

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5 Comments

Kristada673 Over a year ago

I see. But even with this code, it is giving the following error: Invalid argument @ rb_sysopen - C:\Users\Desktop\|x|.csv (Errno::EINVAL).

Aleksei Matiushkin Over a year ago

Ah, interpolated string should be in double quotes, please see an update.

Kristada673 Over a year ago

Ah, I see. I didn't know that! Thanks for sharing this knowledge. Confusing and quirky little language, Ruby. But now even though the code runs without error, it does not produce any output file. Why could that be?

Eric Duminil Over a year ago

Does `C:\Users\Desktop` really exist, or isn't the user name missing?

Kristada673 Over a year ago

@EricDuminil Yeah, fixed it.

Santosh Sharma · Accepted Answer · 2016-12-23 12:39:54Z

2

Change following line

CSV.open('C:\Users\Desktop\#{x}.csv', "wb") do |csv|

to

CSV.open("C:\Users\Desktop\#{x}.csv", "wb") do |csv|

UPDATE

require 'rubygems'
require 'csv'

category_ID = [-1, 0, 1, 2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 15, 17, 18, 19, 20, 21, 91, 92, 93, 94, 101, 102, 103, 104, 105, 106, 107, 111, 112, 113, 114, 115, 116, 117, 118, 119]

CSV.foreach('C:\Users\username\Desktop\Original.csv', :headers=>true) do |row,i|
    category_ID.each do |x|
        CSV.open("C:\Users\username\Desktop\#{x}.csv", "wb") do |csv|           
            if row[4].gsub(/^[^:]+:\s*/,"") == x
                csv << row[28].gsub(/^[^:]+:\s*/,"")
            end
        end
    end
end

edited Dec 23, 2016 at 12:39

answered Dec 23, 2016 at 11:54

Santosh Sharma

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5 Comments

Kristada673 Over a year ago

Ok, the code now runs without error, but it does not produce any output file.

Santosh Sharma Over a year ago

@Kristada673 try this CSV.open("C:\Users\Desktop\#{x}.csv", "a+")

Kristada673 Over a year ago

No, it wouldn't work either, because the file is not even being created. Not even a blank file.

Santosh Sharma Over a year ago

@Kristada673. please see update and try.you forget to write do after .each.remove curly braces.

Kristada673 Over a year ago

Yeah, I saw the small error there, I tried it in the proper way itself. :) No file produced.

peter · Accepted Answer · 2016-12-23 17:12:22Z

1

For the interpolation problem in single quotes, see the answers of mudasobwa and Santosh.

I presume you still get no output because the weird CSV you use. To test this open one of the CSV in the simplest way there is, so no other issues can interfere. I added options to handle malformed CSV. You should see only your data files, nothing else, otherwise filter out the other stuff. Once you are sure your original CSV is read correctly, then try the writing part.

NB the CSV.foreach doesn't provide an index.

CSV.foreach('C:\Users\username\Desktop\Original.csv', :headers=>true, force_quotes: false, :quote_char => "\x00") do |row|
  p row
end

answered Dec 23, 2016 at 17:12

peter

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