Extract consecutive lines of data

ruby-talk
1

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 lines of text ...
....
more text
below is the data to extract

1 2 3
4 5 6
7 8 9
23 7.3e-8 3.4

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

2

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 lines of text ...
> ....
> more text
> below is the data to extract
>
> 1 2 3
> 4 5 6
> 7 8 9
> 23 7.3e-8 3.4
>
>
> 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.

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

···

On Nov 24, 2007 11:13 PM, baptiste Auguié <ba208@exeter.ac.uk> wrote:

--
what do I think about Ruby?
http://ruby-smalltalk.blogspot.com/

3

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 Dober wrote:

On Nov 24, 2007 11:13 PM, baptiste Auguié <ba208@exeter.ac.uk> wrote:

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 lines of text ...
....
more text
below is the data to extract

1 2 3
4 5 6
7 8 9
23 7.3e-8 3.4

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.

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

--
what do I think about Ruby?
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://projects.ex.ac.uk/atto
______________________________

4

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

5

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
p current

Best wishes,

baptiste

···

On 25 Nov 2007, at 12:15, MonkeeSage wrote:

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

_____________________________

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://projects.ex.ac.uk/atto
______________________________

6

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 :wink:

R.

···

On Nov 25, 2007 2:24 PM, baptiste Auguié <ba208@exeter.ac.uk> wrote:

Thanks, this didn't work either (the data file contains lines of text
before and after the data).

--
what do I think about Ruby?
http://ruby-smalltalk.blogspot.com/

7

Happiness! Another vim user. :slight_smile:

Regards,
Jordan

···

On Nov 25, 8:22 am, Robert Dober <robert.do...@gmail.com> wrote:

# vim: sw=2 ts=2 ft=ruby expandtab tw=0 nu syn:

8

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 Dober wrote:

On Nov 25, 2007 2:24 PM, baptiste Auguié <ba208@exeter.ac.uk> 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 :wink:

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://projects.ex.ac.uk/atto
______________________________

9

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!

>> 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 :wink:
>

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 :wink: 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.

···

On Nov 25, 2007 3:53 PM, baptiste Auguié <ba208@exeter.ac.uk> wrote:

On 25 Nov 2007, at 14:22, Robert Dober wrote:
> On Nov 25, 2007 2:24 PM, baptiste Auguié <ba208@exeter.ac.uk> wrote:

_____________________________

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
Attogram Project Site - Index
______________________________

--
what do I think about Ruby?
http://ruby-smalltalk.blogspot.com/