Catting files

ruby-talk
1

Hi ..

There is approximately an order of magnitude difference in the performance of
these two snippets. Is there a faster way of doing the pure Ruby version?

### use the system call 'cat'
def sys_cat
    of = "plato.txt.cat"
    clean(of)
    l = `cat Plato/*.txt > #{of}`
end

### open each file and copy it
def rby_cat
    of = "plato.txt.rby"
    clean(of)
    off = File.new(of, "w+")
    Dir["Plato/*.txt"].each do |f|
        text = IO.readlines(f)
        off.puts text
    end
    off.close
end

                user system total real
sys_cat 0.000000 0.015625 0.117188 ( 0.167577)
rby_cat 0.937500 0.085938 1.023438 ( 1.064247)

Thanks,

···

--
-mark. (probertm at acm dot org)

2

IO.read?
gets(nil)?

···

On Feb 28, 2005, at 9:17 PM, Mark Probert wrote:

Hi ..

There is approximately an order of magnitude difference in the performance of
these two snippets. Is there a faster way of doing the pure Ruby version?

### use the system call 'cat'
def sys_cat
    of = "plato.txt.cat"
    clean(of)
    l = `cat Plato/*.txt > #{of}`
end

### open each file and copy it
def rby_cat
    of = "plato.txt.rby"
    clean(of)
    off = File.new(of, "w+")
    Dir["Plato/*.txt"].each do |f|
        text = IO.readlines(f)
        off.puts text
    end
    off.close
end

                user system total real
sys_cat 0.000000 0.015625 0.117188 ( 0.167577)
rby_cat 0.937500 0.085938 1.023438 ( 1.064247)

Thanks,

--
-mark. (probertm at acm dot org)

3

Mark Probert wrote:

Hi ..

There is approximately an order of magnitude difference in the performance of these two snippets. Is there a faster way of doing the pure Ruby version?

### use the system call 'cat'
def sys_cat
   of = "plato.txt.cat"
   clean(of)
   l = `cat Plato/*.txt > #{of}`
end

### open each file and copy it
def rby_cat
   of = "plato.txt.rby"
   clean(of)
   off = File.new(of, "w+")
   Dir["Plato/*.txt"].each do |f|
       text = IO.readlines(f)
       off.puts text
   end
   off.close
end

               user system total real
sys_cat 0.000000 0.015625 0.117188 ( 0.167577)
rby_cat 0.937500 0.085938 1.023438 ( 1.064247)

Thanks,

Try mine:

def rby_cat
    File.open("file.rby", "w+") do |file|
        Dir["*.txt"].each do |f|
            file.write(IO.readlines(f))
        end
    end
end

4

def faster_cat
    of = "plato.txt.fct"
    clean(of)
    File.open(of, "wb+") do |outf|
      Dir["Plato/*.txt"].each do |inf|
        outf.puts IO::read(inf)
      end
    end
  end

As I don't have the "Plato/*.txt" files, I can't test it, but that
you're not splitting the file into multiple lines and iterating over
them will be faster.

-austin

···

On Tue, 1 Mar 2005 05:17:03 +0900, Mark Probert <probertm@acm.org> wrote:

There is approximately an order of magnitude difference in the
performance of these two snippets. Is there a faster way of doing
the pure Ruby version?

### use the system call 'cat'
def sys_cat
  of = "plato.txt.cat"
  clean(of)
  l = `cat Plato/*.txt > #{of}`
end

--
Austin Ziegler * halostatue@gmail.com
               * Alternate: austin@halostatue.ca

5

Hi ..

···

On Monday 28 February 2005 13:02, Austin Ziegler wrote:

of = &quot;plato\.txt\.fct&quot;
clean\(of\)
File\.open\(of, &quot;wb\+&quot;\) do |outf|
  Dir\[&quot;Plato/\*\.txt&quot;\]\.each do |inf|
    outf\.puts IO::read\(inf\)
  end
end

Perfect!
                user system total real
sys_cat 0.000000 0.007812 0.101562 ( 0.164781)
rb_cat 0.953125 0.070312 1.023438 ( 1.065408)
faster_cat 0.046875 0.078125 0.125000 ( 0.166651)

Thanks, Austin. I knew there was a better way :slight_smile:

--
-mark. (probertm at acm dot org)