# Extract consecutive lines of data **URL:** \ **Category:** Ruby\ **Created:** [November 24, 2007, 11:14pm UTC](https://www.ruby-forum.com/t/extract-consecutive-lines-of-data/121179 "2007-11-24T23:14:54Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![baptiste\_AuguiSSSS](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/71c47a/32.png) [@baptiste\_AuguiSSSS](https://www.ruby-forum.com/u/baptiste_AuguiSSSS)\ **Post date:** [November 24, 2007, 11:14pm UTC](https://www.ruby-forum.com/t/extract-consecutive-lines-of-data/121179/1 "2007-11-24T23:14:54Z")
Hi, A basic question: how to extract several consecutive lines of numbers in a text file (example below) and assign them to some GSL::Matrix in Ruby? text file: > some more text from which i would like to create three vectors, a=[1, 4, 7, 23], b= [2, 5, 8, 7.33-8], c=[3, 6, 9, 3.4]. The line numbers could be used for indexing if that can help. Many thanks, baptiste ---
**Author:** ![baptiste\_AuguiSSSS](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/71c47a/32.png) [@baptiste\_AuguiSSSS](https://www.ruby-forum.com/u/baptiste_AuguiSSSS)\ **Post date:** [November 25, 2007, 1:03am UTC](https://www.ruby-forum.com/t/extract-consecutive-lines-of-data/121179/2 "2007-11-25T01:03:06Z")
On Nov 24, 2007 11:13 PM, baptiste Auguié [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > … > > from which i would like to create three vectors, a=[1, 4, 7, 23], b= > [2, 5, 8, 7.33-8], c=[3, 6, 9, 3.4]. The line numbers could be used > for indexing if that can help. p DATA.readlines.map{ |line| line.chomp.split }.transpose **END** 1 2 3 4 5 6 7 8 9 23 7.3e-8 3.4 > Many thanks, > > baptiste HTH Robert ---
**Author:** ![baptiste\_AuguiSSSS](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/71c47a/32.png) [@baptiste\_AuguiSSSS](https://www.ruby-forum.com/u/baptiste_AuguiSSSS)\ **Post date:** [November 25, 2007, 12:31pm UTC](https://www.ruby-forum.com/t/extract-consecutive-lines-of-data/121179/3 "2007-11-25T12:31:36Z")
Hi, Thanks for the hints, however it doesn’t quite work for me yet. I tried, > p DATA.readlines.map{ |line| line.chomp.split }.transpose > **END** > 1 2 3 > 4 5 6 > 7 8 9 > 23 7.3e-8 3.4 which produces a nice matrix as suggested, but I can’t figure how to read that data from an external file rather than below this “ **END** ” thing ; nor can I see how to deal with the extra text lines above and below the data. This is actually the main problem, as I would otherwise go for > require(“rbgsl”) > a, b, c = GSL::Vector.filescan(filename) Thanks again, baptiste On 25 Nov 2007, at 00:01, Robert D. wrote: > > > some lines of text … > > > some more text > > > 7 8 9 > > – > what do I think about Ruby? > [http://ruby-smalltalk.blogspot.com/](http://ruby-smalltalk.blogspot.com/) * * * Baptiste Auguié Physics Department University of Exeter Stocker Road, Exeter, Devon, EX4 4QL, UK Phone: +44 1392 264187 [http://newton.ex.ac.uk/research/emag](http://newton.ex.ac.uk/research/emag) [http://projects.ex.ac.uk/atto](http://projects.ex.ac.uk/atto) ---
**Author:** ![baptiste\_AuguiSSSS](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/71c47a/32.png) [@baptiste\_AuguiSSSS](https://www.ruby-forum.com/u/baptiste_AuguiSSSS)\ **Post date:** [November 25, 2007, 1:15pm UTC](https://www.ruby-forum.com/t/extract-consecutive-lines-of-data/121179/4 "2007-11-25T13:15:26Z")
def input\_matrix(file) File.open(file) { |f| f.readlines.collect { |line| line = line.chomp if line.empty? then nil else line.split end }.compact.transpose } end p input\_matrix(ARGV[0]) ^ Composes matrix from first file given on command line, ignoring blank lines in file. Regards, Jordan ---
**Author:** ![baptiste\_AuguiSSSS](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/71c47a/32.png) [@baptiste\_AuguiSSSS](https://www.ruby-forum.com/u/baptiste_AuguiSSSS)\ **Post date:** [November 25, 2007, 2:25pm UTC](https://www.ruby-forum.com/t/extract-consecutive-lines-of-data/121179/5 "2007-11-25T14:25:06Z")
Thanks, this didn’t work either (the data file contains lines of text before and after the data). I’ve eventually figured a way playing with different bits of code I found: > # extract space separated numbers from lines 5 to 9 in ‘data.txt’, > > # ignoring header and footer text lines > current = [] > > File.foreach(‘data.txt’) do |line| > if ($. == 5) … ($. == 9) > current \<\< line.scan(/\S+/).map! {|x| x.to\_f} > end > end > p current Best wishes, baptiste On 25 Nov 2007, at 12:15, MonkeeSage wrote: > end > > p input\_matrix(ARGV[0]) > > ^ Composes matrix from first file given on command line, ignoring > blank lines in file. > > Regards, > Jordan * * * Baptiste Auguié Physics Department University of Exeter Stocker Road, Exeter, Devon, EX4 4QL, UK Phone: +44 1392 264187 [http://newton.ex.ac.uk/research/emag](http://newton.ex.ac.uk/research/emag) [http://projects.ex.ac.uk/atto](http://projects.ex.ac.uk/atto) ---
**Author:** ![baptiste\_AuguiSSSS](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/71c47a/32.png) [@baptiste\_AuguiSSSS](https://www.ruby-forum.com/u/baptiste_AuguiSSSS)\ **Post date:** [November 25, 2007, 3:23pm UTC](https://www.ruby-forum.com/t/extract-consecutive-lines-of-data/121179/6 "2007-11-25T15:23:07Z")
On Nov 25, 2007 2:24 PM, baptiste Auguié [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Thanks, this didn’t work either (the data file contains lines of text > before and after the data). grep is your friend 508/8 \> cat data.txt && cat detect.rb && ruby detect.rb data.txt 1 2 3 Some text 4 5 6 more text 7 8 9 .42 42 42 23 7.3e-8 3.4 #!/usr/local/bin/ruby # vim: sw=2 ts=2 ft=ruby expandtab tw=0 nu syn: p ARGF.readlines.grep(/^\s\*[.\d]/).map{ |line| line.chomp.split }.transpose [[“1”, “4”, “7”, “.42”, “23”], [“2”, “5”, “8”, “42”, “7.3e-8”], [“3”, “6”, “9”, “42”, “3.4”]] BTW don’t forget to tell us the mark you got 😉 R. ---
**Author:** ![baptiste\_AuguiSSSS](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/71c47a/32.png) [@baptiste\_AuguiSSSS](https://www.ruby-forum.com/u/baptiste_AuguiSSSS)\ **Post date:** [November 25, 2007, 3:45pm UTC](https://www.ruby-forum.com/t/extract-consecutive-lines-of-data/121179/7 "2007-11-25T15:45:28Z")
On Nov 25, 8:22 am, Robert D. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > # vim: sw=2 ts=2 ft=ruby expandtab tw=0 nu syn: Happiness! Another vim user. 🙂 Regards, Jordan ---
**Author:** ![baptiste\_AuguiSSSS](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/71c47a/32.png) [@baptiste\_AuguiSSSS](https://www.ruby-forum.com/u/baptiste_AuguiSSSS)\ **Post date:** [November 25, 2007, 3:54pm UTC](https://www.ruby-forum.com/t/extract-consecutive-lines-of-data/121179/8 "2007-11-25T15:54:52Z")
Thanks, this is exactly what i was looking for: I just never find my way in these regular expressions, not to mention how to adapt it in Ruby code! On 25 Nov 2007, at 14:22, Robert D. wrote: > On Nov 25, 2007 2:24 PM, baptiste Auguié [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > Thanks, this didn’t work either (the data file contains lines of text > > before and after the data). > > grep is your friend > p ARGF.readlines.grep(/^\s\*[.\d]/).map{ |line| > line.chomp.split }.transpose > > [[“1”, “4”, “7”, “.42”, “23”], [“2”, “5”, “8”, “42”, “7.3e-8”], [“3”, > “6”, “9”, “42”, “3.4”]] > > BTW don’t forget to tell us the mark you got 😉 do you get a mark for a PhD? I can only tell you the imaginary part is gonna be negative, in terms of propagation constant. * * * Baptiste Auguié Physics Department University of Exeter Stocker Road, Exeter, Devon, EX4 4QL, UK Phone: +44 1392 264187 [http://newton.ex.ac.uk/research/emag](http://newton.ex.ac.uk/research/emag) [http://projects.ex.ac.uk/atto](http://projects.ex.ac.uk/atto) ---
**Author:** ![baptiste\_AuguiSSSS](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/71c47a/32.png) [@baptiste\_AuguiSSSS](https://www.ruby-forum.com/u/baptiste_AuguiSSSS)\ **Post date:** [November 25, 2007, 4:47pm UTC](https://www.ruby-forum.com/t/extract-consecutive-lines-of-data/121179/9 "2007-11-25T16:47:45Z")
On Nov 25, 2007 3:53 PM, baptiste Auguié [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > grep is your friend > > #!/usr/local/bin/ruby > > do you get a mark for a PhD? I can only tell you the imaginary part > is gonna be negative, in terms of propagation constant. Well in that case you just state the sources 😉 just kidding, I am aware that Ruby is only doing some “low” stuff, but still glad you use it as a tool, and concerning your PhD “bonne chance”. R.