Asp Forum - extracting values from consecutive lines

baptiste Auguié

10/17/2007 4:03:00 PM

Hello,

This is a basic question, as I'm very new to Ruby. I have a text file
'input.dat' containing the following data and text:

> some text
> some text...
>
> angle value1 value2
>
> 156.00 3.3688E-03 1.7040E-03
> 157.00 3.2919E-03 1.7118E-03
> 158.00 3.2140E-03 1.7190E-03
> 159.00 3.1354E-03 1.7258E-03
> 160.00 3.0560E-03 1.7320E-03
> 161.00 2.9760E-03 1.7378E-03
> 162.00 2.8956E-03 1.7431E-03
> 163.00 2.8148E-03 1.7479E-03
> 164.00 2.7338E-03 1.7523E-03
> 165.00 2.6526E-03 1.7562E-03
> 166.00 2.5714E-03 1.7597E-03
> 167.00 2.4902E-03 1.7628E-03

I would like to extract the 3 columns of data for several consecutive
lines (say, from angle = 158 to 165). These values should be stored
in some array or vector. How can I do that in Ruby?

Many thanks,

baptiste

15 Answers

Phrogz

10/17/2007 4:20:00 PM

On Oct 17, 10:03 am, baptiste Augui? <ba...@exeter.ac.uk> wrote:
> > angle value1 value2
>
> > 156.00 3.3688E-03 1.7040E-03
> > 157.00 3.2919E-03 1.7118E-03
> > 158.00 3.2140E-03 1.7190E-03
> > 159.00 3.1354E-03 1.7258E-03
> > 160.00 3.0560E-03 1.7320E-03
> > 161.00 2.9760E-03 1.7378E-03
> > 162.00 2.8956E-03 1.7431E-03
> > 163.00 2.8148E-03 1.7479E-03
> > 164.00 2.7338E-03 1.7523E-03
> > 165.00 2.6526E-03 1.7562E-03
> > 166.00 2.5714E-03 1.7597E-03
> > 167.00 2.4902E-03 1.7628E-03
>
> I would like to extract the 3 columns of data for several consecutive
> lines (say, from angle = 158 to 165). These values should be stored
> in some array or vector. How can I do that in Ruby?

# Make an array of arrays of numbers
# based on scanning for non-whitespace characters
# (all strings will show up as 0.0)
values = IO.readlines( 'input.dat' ).map{ |line|
line.scan( /\S+/ ).map{ |str| str.to_f }
}

my_range = values.select{ |angle, _|
(158..165).include?( angle )
}

require 'pp'
pp my_range
#=> [[158.0, 0.003214, 0.001719],
#=> [159.0, 0.0031354, 0.0017258],
#=> [160.0, 0.003056, 0.001732],
#=> [161.0, 0.002976, 0.0017378],
#=> [162.0, 0.0028956, 0.0017431],
#=> [163.0, 0.0028148, 0.0017479],
#=> [164.0, 0.0027338, 0.0017523],
#=> [165.0, 0.0026526, 0.0017562]]

John Joyce

10/17/2007 4:33:00 PM

On Oct 17, 2007, at 11:03 AM, baptiste Auguié wrote:

>
> Hello,
>
> This is a basic question, as I'm very new to Ruby. I have a text
> file 'input.dat' containing the following data and text:
>
>
>> some text
>> some text...
>>
>> angle value1 value2
>>
>> 156.00 3.3688E-03 1.7040E-03
>> 157.00 3.2919E-03 1.7118E-03
>> 158.00 3.2140E-03 1.7190E-03
>> 159.00 3.1354E-03 1.7258E-03
>> 160.00 3.0560E-03 1.7320E-03
>> 161.00 2.9760E-03 1.7378E-03
>> 162.00 2.8956E-03 1.7431E-03
>> 163.00 2.8148E-03 1.7479E-03
>> 164.00 2.7338E-03 1.7523E-03
>> 165.00 2.6526E-03 1.7562E-03
>> 166.00 2.5714E-03 1.7597E-03
>> 167.00 2.4902E-03 1.7628E-03
>
>
> I would like to extract the 3 columns of data for several
> consecutive lines (say, from angle = 158 to 165). These values
> should be stored in some array or vector. How can I do that in Ruby?
>
> Many thanks,
>
> baptiste
>
>
>
>
Many ways to approach it of course.
You could use CSV or FasterCSV since your data file is lines (rows)
with columns separated by tabs or spaces.
CSV or FasterCSV might be more useful to do other things also with
the data file.
but you can also just read the first 3 or 4 bytes of each line to
find the lines you want.

baptiste Auguié

10/17/2007 5:05:00 PM

thanks so much!

I'll try and use this array with rgsl now...

Best regards,

baptiste

On 17 Oct 2007, at 17:25, Phrogz wrote:

> On Oct 17, 10:03 am, baptiste Auguié <ba...@exeter.ac.uk> wrote:
>>> angle value1 value2
>>
>>> 156.00 3.3688E-03 1.7040E-03
>>> 157.00 3.2919E-03 1.7118E-03
>>> 158.00 3.2140E-03 1.7190E-03
>>> 159.00 3.1354E-03 1.7258E-03
>>> 160.00 3.0560E-03 1.7320E-03
>>> 161.00 2.9760E-03 1.7378E-03
>>> 162.00 2.8956E-03 1.7431E-03
>>> 163.00 2.8148E-03 1.7479E-03
>>> 164.00 2.7338E-03 1.7523E-03
>>> 165.00 2.6526E-03 1.7562E-03
>>> 166.00 2.5714E-03 1.7597E-03
>>> 167.00 2.4902E-03 1.7628E-03
>>
>> I would like to extract the 3 columns of data for several consecutive
>> lines (say, from angle = 158 to 165). These values should be stored
>> in some array or vector. How can I do that in Ruby?
>
> # Make an array of arrays of numbers
> # based on scanning for non-whitespace characters
> # (all strings will show up as 0.0)
> values = IO.readlines( 'input.dat' ).map{ |line|
> line.scan( /\S+/ ).map{ |str| str.to_f }
> }
>
> my_range = values.select{ |angle, _|
> (158..165).include?( angle )
> }
>
> require 'pp'
> pp my_range
> #=> [[158.0, 0.003214, 0.001719],
> #=> [159.0, 0.0031354, 0.0017258],
> #=> [160.0, 0.003056, 0.001732],
> #=> [161.0, 0.002976, 0.0017378],
> #=> [162.0, 0.0028956, 0.0017431],
> #=> [163.0, 0.0028148, 0.0017479],
> #=> [164.0, 0.0027338, 0.0017523],
> #=> [165.0, 0.0026526, 0.0017562]]
>
>

_____________________________

Baptiste Auguié

Physics Department
University of Exeter
Stocker Road,
Exeter, Devon,
EX4 4QL, UK

Phone: +44 1392 264187

http://newton.ex.ac.uk/res...
http://projects.ex....
______________________________

7stud --

10/17/2007 5:32:00 PM

Gavin Kistner wrote:
> On Oct 17, 10:03 am, baptiste Auguiï¿½ <ba...@exeter.ac.uk> wrote:
>> > 164.00 2.7338E-03 1.7523E-03
>> > 165.00 2.6526E-03 1.7562E-03
>> > 166.00 2.5714E-03 1.7597E-03
>> > 167.00 2.4902E-03 1.7628E-03
>>
>> I would like to extract the 3 columns of data for several consecutive
>> lines (say, from angle = 158 to 165). These values should be stored
>> in some array or vector. How can I do that in Ruby?
>
> # Make an array of arrays of numbers
> # based on scanning for non-whitespace characters
> # (all strings will show up as 0.0)
> values = IO.readlines( 'input.dat' ).map{ |line|
> line.scan( /\S+/ ).map{ |str| str.to_f }
> }
>
> my_range = values.select{ |angle, _|
> (158..165).include?( angle )
> }
>
> require 'pp'
> pp my_range
> #=> [[158.0, 0.003214, 0.001719],
> #=> [159.0, 0.0031354, 0.0017258],
> #=> [160.0, 0.003056, 0.001732],
> #=> [161.0, 0.002976, 0.0017378],
> #=> [162.0, 0.0028956, 0.0017431],
> #=> [163.0, 0.0028148, 0.0017479],
> #=> [164.0, 0.0027338, 0.0017523],
> #=> [165.0, 0.0026526, 0.0017562]]

On my system, this is faster:

start = '> 163.00'
stop = '> 166.00'
results = []
get_line = false

File.foreach("data.txt") do |line|
test_field = line[0, start.length]

if test_field == start
get_line = true
end

if get_line
results << line.split()[1..-1].map{|str| str.to_f}

if test_field == stop
break
end

end
end
--
Posted via http://www.ruby-....

William James

10/17/2007 6:08:00 PM

On Oct 17, 11:03 am, baptiste Augui? <ba...@exeter.ac.uk> wrote:
> Hello,
>
> This is a basic question, as I'm very new to Ruby. I have a text file
> 'input.dat' containing the following data and text:
>
> > some text
> > some text...
>
> > angle value1 value2
>
> > 156.00 3.3688E-03 1.7040E-03
> > 157.00 3.2919E-03 1.7118E-03
> > 158.00 3.2140E-03 1.7190E-03
> > 159.00 3.1354E-03 1.7258E-03
> > 160.00 3.0560E-03 1.7320E-03
> > 161.00 2.9760E-03 1.7378E-03
> > 162.00 2.8956E-03 1.7431E-03
> > 163.00 2.8148E-03 1.7479E-03
> > 164.00 2.7338E-03 1.7523E-03
> > 165.00 2.6526E-03 1.7562E-03
> > 166.00 2.5714E-03 1.7597E-03
> > 167.00 2.4902E-03 1.7628E-03
>
> I would like to extract the 3 columns of data for several consecutive
> lines (say, from angle = 158 to 165). These values should be stored
> in some array or vector. How can I do that in Ruby?
>
> Many thanks,
>
> baptiste

p IO.readlines( 'input.dat').grep( /^\d/ ).
map{|s| s.strip.split.map{|x| x.to_f}}.select{|a|
a.first.between?(158,165) }

Bertram Scharpf

10/17/2007 6:35:00 PM

Hi,

Am Donnerstag, 18. Okt 2007, 01:03:21 +0900 schrieb baptiste Auguié:
>> angle value1 value2
>> 156.00 3.3688E-03 1.7040E-03
>> 157.00 3.2919E-03 1.7118E-03
>> 158.00 3.2140E-03 1.7190E-03
>> 159.00 3.1354E-03 1.7258E-03
>> 160.00 3.0560E-03 1.7320E-03
>> 161.00 2.9760E-03 1.7378E-03
>> 162.00 2.8956E-03 1.7431E-03
>> 163.00 2.8148E-03 1.7479E-03
>> 164.00 2.7338E-03 1.7523E-03
>> 165.00 2.6526E-03 1.7562E-03
>> 166.00 2.5714E-03 1.7597E-03
>> 167.00 2.4902E-03 1.7628E-03
>
> I would like to extract the 3 columns of data for several consecutive lines
> (say, from angle = 158 to 165). These values should be stored in some array
> or vector. How can I do that in Ruby?

Anybody considered ranges?

r = 158..165
file.each { |l|
ang, val1, val2 = l.split.map { |x| Float x }
r === ang and do_sth_with val1, val2
}

r = 158..165
file.each { |l|
ang, val1, val2 = l.split.map { |x| Float x }
case ang
when r then do_sth_with val1, val2
end
}

Does anybody remember flip-flops?

file.each { |l|
ang, val1, val2 = l.split.map { |x| Float x }
iang = ang.floor
if (iang==158)..(iang==165) then
do_sth_with val1, val2
end
}

The floor call is not actually beautiful here but always
keep in mind equality shouldn't be tested for floats.
Flip-flops need equality.

Bertram

--
Bertram Scharpf
Stuttgart, Deutschland/Germany
http://www.bertram-...

7stud --

10/17/2007 7:06:00 PM

William James wrote:
>
> p IO.readlines( 'input.dat').grep( /^\d/ ).
> map{|s| s.strip.split.map{|x| x.to_f}}.select{|a|
> a.first.between?(158,165) }

Better. Still slower.
--
Posted via http://www.ruby-....

William James

10/17/2007 9:59:00 PM

Peña, Botp

10/18/2007 2:31:00 AM

From: 7stud -- [mailto:bbxx789_05ss@yahoo.com]
# William James wrote:
# > p IO.readlines( 'input.dat').grep( /^\d/ ).
# > map{|s| s.strip.split.map{|x| x.to_f}}.select{|a|
# > a.first.between?(158,165) }
#
# Better. Still slower.

how about this,

a=[]
ARGF.each do |line|
if line =~ /158/ .. line =~ /165/
a << line.split.map{|x|x.to_f}
end
end

'just joining the fun in ruby :)
kind regards -botp

William James

10/18/2007 6:10:00 AM

William James wrote:
> On Oct 17, 11:03 am, baptiste Auguié <ba...@exeter.ac.uk> wrote:
> > Hello,
> >
> > This is a basic question, as I'm very new to Ruby. I have a text file
> > 'input.dat' containing the following data and text:
> >
> > > some text
> > > some text...
> >
> > > angle value1 value2
> >
> > > 156.00 3.3688E-03 1.7040E-03
> > > 157.00 3.2919E-03 1.7118E-03
> > > 158.00 3.2140E-03 1.7190E-03
> > > 159.00 3.1354E-03 1.7258E-03
> > > 160.00 3.0560E-03 1.7320E-03
> > > 161.00 2.9760E-03 1.7378E-03
> > > 162.00 2.8956E-03 1.7431E-03
> > > 163.00 2.8148E-03 1.7479E-03
> > > 164.00 2.7338E-03 1.7523E-03
> > > 165.00 2.6526E-03 1.7562E-03
> > > 166.00 2.5714E-03 1.7597E-03
> > > 167.00 2.4902E-03 1.7628E-03
> >
> > I would like to extract the 3 columns of data for several consecutive
> > lines (say, from angle = 158 to 165). These values should be stored
> > in some array or vector. How can I do that in Ruby?
> >
> > Many thanks,
> >
> > baptiste
>
> p IO.readlines( 'input.dat').grep( /^\d/ ).
> map{|s| s.strip.split.map{|x| x.to_f}}.select{|a|
> a.first.between?(158,165) }

Please pardon my perverse prolixity. I threw in a "strip" even though
my subconscious told me it was superfluous.

p IO.readlines( 'input.dat').grep( /^\d/ ).
map{|s| s.split.map{|x| x.to_f}}.select{|a|
a.first.between?(158,165) }

comp.lang.ruby

extracting values from consecutive lines

baptiste Auguié

Phrogz

John Joyce

baptiste Auguié

7stud --

William James

Bertram Scharpf

7stud --

William James

Peña, Botp

William James

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