# Trying to use gsub using variables **URL:** \ **Category:** ruby-talk\ **Created:** [27 September 2008 02:50 UTC](https://rubytalk.org/t/trying-to-use-gsub-using-variables/49320 "2008-09-27T02:50:21Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![John\_Sheahan](https://avatars.discourse-cdn.com/v4/letter/j/ad7895/32.png) [@John\_Sheahan](https://rubytalk.org/u/John_Sheahan)\ **Post date:** [27 September 2008 02:50 UTC](https://rubytalk.org/t/trying-to-use-gsub-using-variables/49320/1 "2008-09-27T02:50:21Z")
I need to be able to match and substitute text in a string and I'm trying to use gsub with no luck....probably because it's looking for an regular expression. Does anyone know how I can achieve this same thing using another method perhaps? Here is my code that is not working: x = "NEW\_WORD" acl.gsub!(/WORD\_TO\_MATCH\_AND\_REPLACE/, x ) thanks jackster > **···** > > -- > Posted via [http://www.ruby-forum.com/](http://www.ruby-forum.com/). ---
**Author:** ![\_RK\_Sentinel](https://avatars.discourse-cdn.com/v4/letter/_/45deac/32.png) [@\_RK\_Sentinel](https://rubytalk.org/u/_RK_Sentinel)\ **Post date:** [27 September 2008 03:18 UTC](https://rubytalk.org/t/trying-to-use-gsub-using-variables/49320/2 "2008-09-27T03:18:32Z")
jackster the jackle wrote: > Here is my code that is not working: > > x = "NEW\_WORD" > acl.gsub!(/WORD\_TO\_MATCH\_AND\_REPLACE/, x ) the x is fine, your text inside the /../ would be wrong. e.g. irb(main):025:0\> u="Oct" =\> "Oct" irb(main):026:0\> s =\> "abc def Sep 10 10:22 filename" irb(main):027:0\> s.gsub(/Sep/,u) =\> "abc def Oct 10 10:22 filename" > **···** > > -- > Posted via [http://www.ruby-forum.com/\](http://www.ruby-forum.com/%5C). ---
**Author:** ![Robert\_K1](https://yyz1.discourse-cdn.com/flex029/user_avatar/rubytalk.org/robert_k1/32/1830_2.png) [@Robert\_K1](https://rubytalk.org/u/Robert_K1)\ **Post date:** [27 September 2008 09:29 UTC](https://rubytalk.org/t/trying-to-use-gsub-using-variables/49320/3 "2008-09-27T09:29:34Z")
How do you know? OP has neither posted what's in "acl" nor what he intends to replace.   robert > **···** > > On 27.09.2008 05:18, Nit Khair wrote: > > > jackster the jackle wrote: > > > > > Here is my code that is not working: > > > > > > x = "NEW\_WORD" > > > acl.gsub!(/WORD\_TO\_MATCH\_AND\_REPLACE/, x ) > > > > the x is fine, your text inside the /../ would be wrong. ---
**Author:** ![John\_Sheahan](https://avatars.discourse-cdn.com/v4/letter/j/ad7895/32.png) [@John\_Sheahan](https://rubytalk.org/u/John_Sheahan)\ **Post date:** [27 September 2008 12:22 UTC](https://rubytalk.org/t/trying-to-use-gsub-using-variables/49320/4 "2008-09-27T12:22:55Z")
thanks guys...I'm making progress but what I have been slowly leading up to is searching using a variable then replacing it with a variable. acl = "now is the time" x = time y = TEST acl.gsub(/x/,y) How do I get gsub to use the value of x rather "x" itself in my match? thanks Jackster > **···** > > -- > Posted via [http://www.ruby-forum.com/](http://www.ruby-forum.com/). ---
**Author:** ![Tim\_Hunter4](https://avatars.discourse-cdn.com/v4/letter/t/ea5d25/32.png) [@Tim\_Hunter4](https://rubytalk.org/u/Tim_Hunter4)\ **Post date:** [27 September 2008 12:54 UTC](https://rubytalk.org/t/trying-to-use-gsub-using-variables/49320/5 "2008-09-27T12:54:15Z")
jackster the jackle wrote: > thanks guys...I'm making progress but what I have been slowly leading up to is searching using a variable then replacing it with a variable. > > acl = "now is the time" > x = time > y = TEST > > acl.gsub(/x/,y) > > How do I get gsub to use the value of x rather "x" itself in my match? > > thanks > > Jackster /#{x}/ > **···** > > -- > RMagick: [http://rmagick.rubyforge.org/](http://rmagick.rubyforge.org/) ---
**Author:** ![John\_Sheahan](https://avatars.discourse-cdn.com/v4/letter/j/ad7895/32.png) [@John\_Sheahan](https://rubytalk.org/u/John_Sheahan)\ **Post date:** [28 September 2008 01:03 UTC](https://rubytalk.org/t/trying-to-use-gsub-using-variables/49320/6 "2008-09-28T01:03:43Z")
thanks...I got that to work...now for my last question...I am trying to match on a hash value. I have a text file that gets opened with 4 different types of statements in it...the values are contained in my hash called "h". The values in the hash are (IN,OUT,PP,AA). @acl\_list contains a bunch of firewall rules that either have the value IN,OUT,PP or AA in them. What I am trying to do is loop through @acl\_list, substitute the value of h with the key (which works great) but then, I need to put the number 1 in the first firewall rule that contains IN, then the number 2 in the second firewall rule that contains IN etc. When I'm finished with the "IN" rules, I want to do the same thing for "OUT","PP" and "AA". What I have here works great but only for the "IN" rules: k= 1 @acl\_list.each do |acl|   h.each {|key,value|   acl.gsub!(/#{key}/,value)}   if acl[/IN/]     acl.gsub!(/^/,k.to\_s)     k+=1     puts acl   end What I really need is to match on the value of the hash, then add the numbers to the beginning of each line. I thought the following would work but it doen't (although #{value} does have the correct info in it). Can anyone help me figure out how I can get the loop to match on the value of my hash? I think if I can get this to work, everything will be the way I need it. k= 1 @acl\_list.each do |acl|   h.each {|key,value|   acl.gsub!(/#{key}/,value)}   if acl[/#{value}/]     acl.gsub!(/^/,k.to\_s)     k+=1     puts acl   end Thanks again! jackster Here's an example of what is actually contained in @acl\_list: access-list IN permit tcp 172.2.1.0 255.255.0.0 172.1.1.0 255.255.255.0 eq ftp access-list IN permit tcp 10.1.1.0 255.255.0.0 172.1.10 255.255.255.0 eq 13782 access-list IN permit tcp 10.1.1.0 255.255.0.0 172.1.1.0 255.255.255.0 eq ftp access-list OUT permit tcp 10.1.1.0 255.255.0.0 172.1.1.0 255.255.255.0 eq ftp access-list OUT permit tcp 10.1.1.0 255.255.0.0 172.1.1.0 255.255.255.0 eq ftp access-list PP permit tcp 172.1.0.0 255.0.0.0 172.1.1.0 255.255.255.0 eq www access-list PP permit tcp 172.1.0.0 255.0.0.0 172.1.1.0 255.255.0.0 eq ftp access-list PP permit tcp 172.1.0.0 255.0.0.0 172.1.100.0 255.255.0.0 eq ssh access-list AA permit tcp 172.2.0.0 255.0.0.0 172.1.1.0 255.255.0.0 eq www access-list AA permit tcp 172.22.0.0 255.255.0.0 172.21.100.0 255.0.0.0 eq 8080 My end result is that I want these same rules to look like this: 1 access-list IN permit tcp 172.2.1.0 255.255.0.0 172.1.1.0 255.255.255.0 eq ftp 2 access-list IN permit tcp 10.1.1.0 255.255.0.0 172.1.10 255.255.255.0 eq 13782 3 access-list IN permit tcp 10.1.1.0 255.255.0.0 172.1.1.0 255.255.255.0 eq ftp 1 access-list OUT permit tcp 10.1.1.0 255.255.0.0 172.1.1.0 255.255.255.0 eq ftp 2 access-list OUT permit tcp 10.1.1.0 255.255.0.0 172.1.1.0 255.255.255.0 eq ftp 1 access-list PP permit tcp 172.1.0.0 255.0.0.0 172.1.1.0 255.255.255.0 eq www 2 access-list PP permit tcp 172.1.0.0 255.0.0.0 172.1.1.0 255.255.0.0 eq ftp 3 access-list PP permit tcp 172.1.0.0 255.0.0.0 172.1.100.0 255.255.0.0 eq ssh 1 access-list AA permit tcp 172.2.0.0 255.0.0.0 172.1.1.0 255.255.0.0 eq www 2 access-list AA permit tcp 172.22.0.0 255.255.0.0 172.21.1.0 255.0.0.0 eq www > **···** > > -- > Posted via [http://www.ruby-forum.com/](http://www.ruby-forum.com/). ---
**Author:** ![Robert\_K1](https://yyz1.discourse-cdn.com/flex029/user_avatar/rubytalk.org/robert_k1/32/1830_2.png) [@Robert\_K1](https://rubytalk.org/u/Robert_K1)\ **Post date:** [28 September 2008 08:49 UTC](https://rubytalk.org/t/trying-to-use-gsub-using-variables/49320/7 "2008-09-28T08:49:19Z")
It seems you are doing this too complicated and making your life harder than necessary. If I read you correctly this is what you want to do: you want to read a file where each line falls in one of four \*fixed\* classes (IN, OUT...). You want to number each class individually and print that out. If you use a Hash you can do something like this (proper variable naming goes a long way in making this readable and understandable): counters = Hash.new 0 ARGF.each do |line|    line\_class = line[/\b(?:IN|OUT|PP|AA)\b/]    raise "Unknown rule" unless line\_class    print counters[line\_class] += 1, " ", line end Cheers   robert > **···** > > On 28.09.2008 03:03, jackster the jackle wrote: > > > thanks...I got that to work...now for my last question...I am trying to match on a hash value. I have a text file that gets opened with 4 different types of statements in it...the values are contained in my hash called "h". The values in the hash are (IN,OUT,PP,AA). @acl\_list contains a bunch of firewall rules that either have the value IN,OUT,PP or AA in them. What I am trying to do is loop through @acl\_list, substitute the value of h with the key (which works great) but then, I need to put the number 1 in the first firewall rule that contains IN, then the number 2 in the second firewall rule that contains IN etc. > > When I'm finished with the "IN" rules, I want to do the same thing for "OUT","PP" and "AA". > > > > What I have here works great but only for the "IN" rules: > > > > k= 1 > > @acl\_list.each do |acl| > >   h.each {|key,value| > >   acl.gsub!(/#{key}/,value)} > >   if acl[/IN/] > >     acl.gsub!(/^/,k.to\_s) > >     k+=1 > >     puts acl > >   end > > > > What I really need is to match on the value of the hash, then add the numbers to the beginning of each line. I thought the following would work but it doen't (although #{value} does have the correct info in it). Can anyone help me figure out how I can get the loop to match on the value of my hash? I think if I can get this to work, everything will be the way I need it. > > > > k= 1 > > @acl\_list.each do |acl| > >   h.each {|key,value| > >   acl.gsub!(/#{key}/,value)} > >   if acl[/#{value}/] > >     acl.gsub!(/^/,k.to\_s) > >     k+=1 > >     puts acl > >   end ---
**Author:** ![Robert\_K1](https://yyz1.discourse-cdn.com/flex029/user_avatar/rubytalk.org/robert_k1/32/1830_2.png) [@Robert\_K1](https://rubytalk.org/u/Robert_K1)\ **Post date:** [28 September 2008 09:19 UTC](https://rubytalk.org/t/trying-to-use-gsub-using-variables/49320/8 "2008-09-28T09:19:20Z")
PS: Forgot to mention that you may have to adjust the regexp matching to be more robust. In your case you may want to do line\_class = line[/^access-list\s+(IN|OUT|PP|AA)\b/, 1] Cheers   robert > **···** > > On 28.09.2008 10:46, Robert Klemme wrote: > > > If you use a Hash you can do something like this (proper variable naming goes a long way in making this readable and understandable): > > > > counters = Hash.new 0 > > > > ARGF.each do |line| > >   line\_class = line[/\b(?:IN|OUT|PP|AA)\b/] > >   raise "Unknown rule" unless line\_class > >   print counters[line\_class] += 1, " ", line > > end ---
**Author:** ![John\_Sheahan](https://avatars.discourse-cdn.com/v4/letter/j/ad7895/32.png) [@John\_Sheahan](https://rubytalk.org/u/John_Sheahan)\ **Post date:** [28 September 2008 10:07 UTC](https://rubytalk.org/t/trying-to-use-gsub-using-variables/49320/9 "2008-09-28T10:07:39Z")
Thanks alot Robert....I'm not familiar with ARGF so I'm having a bit of trouble getting the code you sent properly inserted into what I already have. What does the ARGF do? thanks again jackster > **···** > > -- > Posted via [http://www.ruby-forum.com/](http://www.ruby-forum.com/). ---
**Author:** ![Robert\_K1](https://yyz1.discourse-cdn.com/flex029/user_avatar/rubytalk.org/robert_k1/32/1830_2.png) [@Robert\_K1](https://rubytalk.org/u/Robert_K1)\ **Post date:** [29 September 2008 05:55 UTC](https://rubytalk.org/t/trying-to-use-gsub-using-variables/49320/10 "2008-09-29T05:55:28Z")
What did you find out so far? robert > **···** > > 2008/9/28 jackster the jackle \: > > > Thanks alot Robert....I'm not familiar with ARGF so I'm having a bit of > > trouble getting the code you sent properly inserted into what I already > > have. > > > > What does the ARGF do? > > -- > remember.guy do |as, often| as.you\_can - without end