From: Phrogz <phrogz@...>
Date: 2007-10-18T01:25:03+09:00
Subject: Re: extracting values from consecutive lines

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]]