Write output to multiple files

[Milo Thurston]

I have encountered something I thought would be trivial but I can't
quite get it to work properly. I have a load of data that is stored in
various locations and need to create several files, one for each
location, each containing the data in that location. Getting an array of
objects containing the file name and location is easy, so I was thinking
along the lines of this pseudocode:

data.each do |d|
output_filename = "#{d.location}.txt"
if !File.exists?(output_filename)
# create it and write d.file_name to it
else
# simply write d.file_name to it
end
end
# close all open files

The locations of the data are numerical ids so I could expect filenames
like 1.txt, 2.txt and so on, and I have also sorted them before
processing so that they could be opened and filled sequentially. But, it
is not clear to me how to properly manage the file handles so any
suggestions would be welcome.

 

[Milo Thurston]

If I understood you properly:

# untested
last_name = nil
io = nil
begin
data.sort_by {|d| d.location}.each do |d|
output_filename = "#{d.location}.txt"

unless output_filename == last_name
io.close rescue nil
io = File.open(output_filename, "a")
end

io.puts d.file_name
ensure
io.close rescue nil
end

Yes, that looks like just the job, thanks. I was trying something
similar but without the begin/ensure/end block and that is presumably
why I was having difficulty.