string = “root 14051 14033 3 08:39 pts/2 00:00:00 /bin/bash”
i need to fetch 14051 and /bin/bash from the string
can someone help me to write an efficient regular expression for that.
i am a beginner, i wrote
string =~ /(\d+)\s+(\d+)\s+\d+\s+\d+:\d+\s+.\s+\d+:\d+:\d+\s+(.)\s/
i know this is not the efficient way of doing it.
Please help.
Divya B. wrote:
string = “root 14051 14033 3 08:39 pts/2 00:00:00 /bin/bash”
i need to fetch 14051 and /bin/bash from the string
i mean i need the 2nd column and the last column.
can someone help me to write an efficient regular expression for that.
i am a beginner, i wrote
string =~ /(\d+)\s+(\d+)\s+\d+\s+\d+:\d+\s+.\s+\d+:\d+:\d+\s+(.)\s/i know this is not the efficient way of doing it.
Please help.
On Jul 10, 2007, at 3:25 PM, Divya B. wrote:
Divya B. wrote:
string = “root 14051 14033 3 08:39 pts/2 00:00:00 /bin/bash”
i need to fetch 14051 and /bin/bash from the string
i mean i need the 2nd column and the last column.
cols = string.split
sec, last = cols.values_at(1, -1)
Hope that helps.
James Edward G. II
Hi Divya, use
string[/\s(\d+)/, 1]
see String.[]
Regards
Florian
Florian Aßmann schrieb:
Hi Divya, use
string[/\s(\d+)/, 1]
see String.[]
Regards
Florian
pid = string[/\s(\d+)/, 1]
cmd = string[/\s(\S+)$/, 1] # is missing
Florian Aßmann wrote:
Hi Divya, use
string[/\s(\d+)/, 1]
see String.[]
Regards
Florian
string = “root 14051 14033 3 08:39 pts/2 00:00:00 /bin/bash”
with this,
string =~ /(\d+)\s+(\d+)\s+\d+\s+\d+:\d+\s+.\s+\d+:\d+:\d+\s+(.)\s/
$1 gives me 14051
and
$3 gives me /bin/bash
what i am trying to do is to get $1 and $3 into a hash.
I love regex, so it hurts me to say it, there are other ways of solving
this 
for instance:
string = “root 14051 14033 3 08:39 pts/2 00:00:00 /bin/bash”
number = string.split[1]
program=string.split.last
now regexes!
string = “root 14051 14033 3 08:39 pts/2 00:00:00 /bin/bash”
number=string[/[0-9]+/]
program=string[/[a-z/]+$/]
You know you can get values out of an array with the [] operator.
Well you can get strings out of strings that same way, and it works
with regexes!
string[/[0-9]+/] will return the first match of 1 or more numbers
Here’s the magic use [ ] inside of a regular expression to create your
own groups. Individual characters in there are included in the group,
and ranges may be included using the -. so a-b is
abcdefghijklmnopqrstuvwxyz.
The + afterwards means 1 or more times.
What if you want _exactly 5 consecutive numbers? use the {}
string[/[0-9]{5}/]
ranges also work here
string[/[0-9]{3-5}/] would match 3, 4 or 5 digit numbers
and
string[/[a-z/]+$/] will match a text string containing the forward
slash at the end. The $ is a special char to represent the end of a
line, and since / is a special char itself, it needed to be escaped
with a .
BUT it could even be easier.
the [] groups, can be negative!
/[^a]/ would match any string that did not have an a in it
/[^ ]/ would match any string that did not have a space in it…soo
string[/[^ ]+$/] would be a good way to get the last bit.
Ooooh fun.
so are you going to announce the winner
On 7/10/07, James Edward G. II [email protected] wrote:
sec, last = cols.values_at(1, -1)
Very interesting James, I seem to be rather extreme and
sec, last = string.split.values_at(1, -1)
might be a tad to long for one line in your style, however Ruby syntax
just supports this marvelous syntax 
sec, last = string.split.
values_at(1, -1)
Robert
Divya B. schrieb:
Please help.
talking about efficient, I was just curious…
#!/usr/bin/env ruby -w
string = “root 14051 14033 3 08:39 pts/2 00:00:00 /bin/bash”
require ‘profiler’
puts <<-EOS
pid = string[/\s(\d+)/, 1]
cmd = string[/\s(\S+)$/, 1]
EOS
Profiler__::start_profile
10000.times do
pid = string[/\s(\d+)/, 1]
cmd = string[/\s(\S+)$/, 1]
end
Profiler__::stop_profile
Profiler__::print_profile STDOUT
puts <<-EOS
cols = string.split
sec, last = cols.values_at(1, -1)
EOS
Profiler__::start_profile
10000.times do
cols = string.split
sec, last = cols.values_at(1, -1)
end
Profiler__::stop_profile
Profiler__::print_profile STDOUT
puts <<-EOS
number = string.split[1]
program = string.split.last
EOS
Profiler__::start_profile
10000.times do
number = string.split[1]
program = string.split.last
end
Profiler__::stop_profile
Profiler__::print_profile STDOUT
grin
Florian
On 7/10/07, Kyle S. [email protected] wrote:
Ooooh fun.
so are you going to announce the winner
It’s just profiler code, you can run it yourself… But on my machine:
pid = string[/ (d+)/, 1]
cmd = string[/ (S+)$/, 1]
% cumulative self self total
time seconds seconds calls ms/call ms/call name
58.26 0.67 0.67 1 670.00 1150.00 Integer#times
41.74 1.15 0.48 20000 0.02 0.02 String#[]
0.00 1.15 0.00 1 0.00 1150.00 #toplevel
cols = string.split
sec, last = cols.values_at(1, -1)
% cumulative self self total
time seconds seconds calls ms/call ms/call name
66.67 0.70 0.70 1 700.00 1050.00 Integer#times
18.10 0.89 0.19 10000 0.02 0.02 String#split
15.24 1.05 0.16 10000 0.02 0.02 Array#values_at
0.00 1.05 0.00 1 0.00 1050.00 #toplevel
number = string.split[1]
program = string.split.last
% cumulative self self total
time seconds seconds calls ms/call ms/call name
61.70 1.16 1.16 1 1160.00 1880.00 Integer#times
23.94 1.61 0.45 20000 0.02 0.02 String#split
8.51 1.77 0.16 10000 0.02 0.02 Array#last
5.85 1.88 0.11 10000 0.01 0.01 Array#[]
0.00 1.88 0.00 1 0.00 1880.00 #toplevel
Ok, it was hard to beat Edward, but at least building the simplest
regular expression to do somthing like a String.split seems to faster:
#!/usr/bin/env ruby -w
string = “root 14051 14033 3 08:39 pts/2 00:00:00 /bin/bash”
require ‘profiler’
puts <<-EOS
pid_rx = /\s(\d+)/
cmd_rx = /\s(\S+)$/
pid, cmd = string[pid_rx, 1], string[cmd_rx, 1]
EOS
Profiler__::start_profile
pid_rx = /\s(\d+)/
cmd_rx = /\s(\S+)$/
100000.times do
pid, cmd = string[pid_rx, 1], string[cmd_rx, 1]
end
Profiler__::stop_profile
Profiler__::print_profile STDOUT
puts <<-EOS
pid, cmd = string.split.values_at(1, -1)
EOS
Profiler__::start_profile
100000.times do
pid, cmd = string.split.values_at(1, -1)
end
Profiler__::stop_profile
Profiler__::print_profile STDOUT
puts <<-EOS
rx = Regexp.new(’\S+\s(\d+).*\s(\S+$)’)
pid, cmd = rx.match(string).values_at( 1, -1 )
EOS
Profiler__::start_profile
rx = Regexp.new(’\S+\s(\d+).*\s(\S+$)’)
100000.times do
pid, cmd = rx.match(string).values_at( 1, -1 )
end
Profiler__::stop_profile
Profiler__::print_profile STDOUT
puts <<-EOS
rx = Regexp.new(’(\S+)’)
pid, cmd = rx.match(string).values_at( 1, -1 )
EOS
Profiler__::start_profile
rx = Regexp.new(’(\S+)’)
100000.times do
pid, cmd = rx.match(string).values_at( 1, -1 )
end
Profiler__::stop_profile
Profiler__::print_profile STDOUT
Sincerely
Florian
except that the last regexp match sh**… lol
On 7/10/07, Robert D. [email protected] wrote:
cols = string.split
sec, last = cols.values_at(1, -1)
Very interesting James, I seem to be rather extreme andsec, last = string.split.values_at(1, -1)
might be a tad to long for one line in your style, however Ruby syntax
just supports this marvelous syntaxsec, last = string.split.
values_at(1, -1)
What is your terminal width, 30?
sorry for being OT since I’m not going to talk about ruby or regexp
If the string you’re parsing is an output from the ps command you can
simplify your life using the -o option that prints only the fields you
need.
I.E. in gnu Linux
ps -ao pid,command
just outputs pid and command columns.
Be careful since the command column can contain spaces.
Paolo
Robert D. wrote:
On 7/10/07, James Edward G. II [email protected] wrote:
sec, last = cols.values_at(1, -1)
Very interesting James, I seem to be rather extreme andsec, last = string.split.values_at(1, -1)
might be a tad to long for one line in your style, however Ruby syntax
just supports this marvelous syntaxsec, last = string.split.
values_at(1, -1)Robert
cmd = string[/\s(\S+)$/, 1]
doesnt fetch me anything:)
program=string.split.last
what if
string = “root 14051 14033 3 08:39 pts/2 00:00:00 /bin/bash -x
-s”
it fetches only -s for me.
sec, last = string.split.values_at(1, -1)
doesnt work for the same reason
i need everything after 00.00.00 till the end
i.e., /bin/bash -x -s
program=string[/[a-z/]+$/]
the command column mauy start with character. i dont want to limit it in
my regexp. it has to be generic.
with all your comments, i tried
pid = run_process[/\s(\d+)/, 1]
cmd = run_process[/:\d+:\d+\s(\S.*)\s$/, 1]
is there any other way?
Paolo N. wrote:
sorry for being OT since I’m not going to talk about ruby or regexp
If the string you’re parsing is an output from the ps command you can
simplify your life using the -o option that prints only the fields you
need.I.E. in gnu Linux
ps -ao pid,command
just outputs pid and command columns.
Be careful since the command column can contain spaces.Paolo
i saw that too. But i can not use all the options in a ps command where
i am using.
i am limited to using ps -aef
i need to take care of fetching the stuff i need using from this result.
On 7/10/07, Divya B. [email protected] wrote:
values_at(1, -1)it fetches only -s for me.
pid = run_process[/\s(\d+)/, 1]
cmd = run_process[/:\d+:\d+\s(\S.*)\s$/, 1]is there any other way?
It’s not fancy, but I’ll throw it in:
s = ‘root 14051 14033 3 08:39 pts/2 00:00:00 /bin/bash -x -s’
_, pid, _, cmd = (s.match /(\d+)\s.(:\d+){2}\s(.*?)$/)
so, if you’re using a hash like I think you might be:
s =
h = {}
s.each_line do |line|
_, pid, _, cmd = (line.match /(\d+)\s.(:\d+){2}\s(.*?)$/)
h[pid] = cmd
end
I think that should work.
Todd
_, pid
Just limit the split and you should go with command arguments…
On Jul 10, 2007, at 7:54 PM, Florian Aßmann wrote:
Just limit the split and you should go with command arguments…
…unless the process start time is one of the output columns and it
goes from ‘HH:MM’ to ‘Mon dd’ for a process that runs long enough.
If you really can’t change the ps options, suck it up, count columns,
forget the regexp, and be done.
-Rob
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