Question

I am trying to pass in the file extension as a variable but it doesn’t seem to be working. when I run getlist.rb(txt)

def getlist(extension)
  file = File.new("the_list.txt", "w")
  Dir['../path/*.'+ extension].each { |f| file.puts File.basename(f, '.'+ extension).upcase }
end

Basically I want to drop in any file extension (txt, pdf, rb, etc) and it will give me the list without the extension names. Script works fine when it is hard coded just doesn’t work when I try to drop in a variable.

Best Regards,

AZCards

Answer 1

My example:

def getlist(extension)
  File.open("the_list.txt", "w"){|file|
    Dir["*.#{extension}"].each { |f| 
        file << File.basename(f, File.extname(f)).upcase
        file << "\n"
    }
  }
end

getlist('rb')
getlist(:rb)

My main modifications:

• File.open isnted new (you forgot file.close). With File.open and a block the close is done automatic.
• Replaces String+ with #-replacements. Advantage: you can use symbols when you call it (you wrote getlist.rb(txt) – this only works, when txt is a variable, but I think you want ‘txt’)
• Use File#extension., see Daves answer.
• I added newlines to the resulting file.

Update
Just in case you need a solution with multiple extensions and to call it from command line:

def getlist(*extensions)
  p "*.{#{extensions.join(',')}}"
  File.open("the_list.txt", "w"){|file|
    Dir["*.{#{extensions.join(',')}}"].each { |f| 
        file << File.basename(f, File.extname(f)).upcase
        file << "\n"
    }
  }
end

#getlist('rb', 'txt')
#getlist(:rb, :txt)
getlist(*ARGV)