How to call gnuplot from ruby?

Ruby
1

i want to call gnuplot from ruby,my ruby script:
gnuplot <<EOF
plot sin(x)
EOF

pt@pt-laptop:~$ ruby /home/pt/r.rb ,then i get :

G N U P L O T
Version 4.2 patchlevel 6
last modified Sep 2009
System: Linux 2.6.32-22-generic

Copyright (C) 1986 - 1993, 1998, 2004, 2007 - 2009
Thomas W., Colin Kelley and many others

Type help to access the on-line reference manual.
The gnuplot FAQ is available from gnuplot FAQ

Send bug reports and suggestions to
http://sourceforge.net/projects/gnuplot

Terminal type set to ‘wxt’

2

On 27 May 2010 13:07, Pen T. [email protected] wrote:

last modified Sep 2009

Terminal type set to ‘wxt’

Posted via http://www.ruby-forum.com/.

With popen:

IO.popen(‘gnuplot’, ‘w’) { |io|
io.puts “plot sin(x)”
}

If you want easier control for reading/writing, use open3.

B.D.

3

IO.popen(‘gnuplot’, ‘w’) { |io|
io.puts “plot sin(x)”
}
i tested ,it’s ok
but i don’t understand why is (‘gnuplot’, ‘w’),why is not (‘gnuplot’,
‘r’),
i call gunplot from ruby to get gnuplot’s output ,so maybe it’s
(‘gnuplot’, ‘r’),
when i use (‘gnuplot’, ‘r’), can’t get what i want,
could you tell me the reason of (‘gnuplot’, ‘w’)?

4

On Fri, May 28, 2010 at 2:51 AM, Pen T. [email protected] wrote:

IO.popen(‘gnuplot’, ‘w’) { |io|
io.puts “plot sin(x)”
}
i tested ,it’s ok
but i don’t understand why is (‘gnuplot’, ‘w’),why is not (‘gnuplot’,
‘r’),
you are writing to the handle, right?
BTW were there not some Ruby bindings for Gnuplot, not sure though.
HTH
R.

5

i don’t know the difference of w and r.
program_a1:
f=IO.popen(“gunzip -c ~/grid.zip”,“w”)
while line=f.gets
print line
end
program_a2:
f=IO.popen(“gunzip -c ~/grid.zip”,“r”)
while line=f.gets
print line
end
program_a1 and program_a2 all can run ,what’s the difference?

there is game–freeciv installed in my computer.
programb1:
File.popen("/usr/games/civ",“w”) do |pipe|
quote = pipe.gets
puts quote
end

programb2:
File.popen("/usr/games/civ",“r”) do |pipe|
quote = pipe.gets
puts quote
end
program_b1 and program_b2 all can run ,what’s the difference?

6

Robert D. wrote:

On Fri, May 28, 2010 at 2:51 AM, Pen T. [email protected] wrote:

IO.popen(‘gnuplot’, ‘w’) { |io|
io.puts “plot sin(x)”
}
i tested ,it’s ok
but i don’t understand why is (‘gnuplot’, ‘w’),why is not (‘gnuplot’,
‘r’),
you are writing to the handle, right?
BTW were there not some Ruby bindings for Gnuplot, not sure though.

There is a gnuplot gem which IIRC makes the gnuplot interface more
object oriented.

I wrote a library that retains the native gnuplot command interface, but
improves the experience in other ways (handling tempfiles and fixing
some problems with window persistence and zombie processes). See this
thread, for example:

http://groups.google.com/group/comp.lang.ruby/browse_thread/thread/b69fce4b8b6b002b

7

Lars H. wrote:

The latest version of the gnuplot gem is 2.3.1, but I’m unable to find
any documentation online (or even a homepage) that is even remotely up
to date.

http://rgplot.rubyforge.org/

It look a little out of date, but maybe it helps?

8

BTW were there not some Ruby bindings for Gnuplot, not sure though.

There is a gnuplot gem which IIRC makes the gnuplot interface more
object oriented.

The latest version of the gnuplot gem is 2.3.1, but I’m unable to find
any documentation online (or even a homepage) that is even remotely up
to date.