how to change a character in all documents (4)

Wednesday, 26 January 2011 15:26

content_mofified-|file_name|-data-dir[argv[0]]each-file

Lets define a write() method in File class :



class File

 def self.write(name)

   data = yield

   self.open(name,"w") { |f| f.write( data ) }

 end

end

Now code with Dir[exp] , File.read(), File.write() :



Dir[ARGV[0]].each() do |file_name|

 file_content     = File.read(file_name)

 content_mofified = file_content.gsub(/a/,"@")

 File.write(file_name) { content_mofified }

end

Ruby -is- Block and meta-programming
without this, it's a python/php/...

Or, more functional :



Dir[ARGV[0]].each() { |file_name|  

  File.write(file_name) { File.read(file_name).gsub(/a/,"@") } 

}

This is the best form, because it don't use local variable
==> provable
==> threadable without danger