Morton Goldberg
6/30/2007 12:03:00 PM
On Jun 30, 2007, at 6:37 AM, baptiste Auguié wrote:
> Being used to deal with Octave / Matlab, I'm a bit confused by Ruby
> structures (arrays, hashes, etc). I have this data file "data.dat"
> with 3 columns:
>
>
>> 1.240000 9.990000e-01 1.290000e-06
>> 1.550000 1.000000e+00 2.920000e-06
>> 2.066000 1.002000e+00 8.360000e-06
>> 2.480000 1.001000e+00 1.520000e-05
>> 2.755000 1.001000e+00 2.210000e-05
>> 3.099000 1.003000e+00 3.570000e-05
>> 3.444000 1.003000e+00 3.240000e-05
>> 3.542000 1.003000e+00 1.720000e-05
>> 4.133000 1.001000e+00 1.430000e-05
>> 4.959000 1.001000e+00 2.400000e-05
>> 6.199000 1.001000e+00 4.720000e-05
>> 8.265000 9.990000e-01 1.210000e-04
>
> I would like to think of the columns as arrays "a", "b", "c",
> execute a loop along their indices, pick the values i want, and do
> something with them. What would be a sensible data structure for this?
> I can read this datafile line by line using IO:readlines
> ("data.dat"), but I cannot find a way to refer to one column in the
> array of strings generated.
Maybe something like this is what you're looking for:
<code>
data = DATA.readlines
rows = data.map do |row|
row.split(/\s+/).map { |elt| elt.to_f }
end
a, b, c = rows.transpose
p a, b, c
__END__
1.240000 9.990000e-01 1.290000e-06
1.550000 1.000000e+00 2.920000e-06
2.066000 1.002000e+00 8.360000e-06
2.480000 1.001000e+00 1.520000e-05
</code>
<result>
[1.24, 1.55, 2.066, 2.48]
[0.999, 1.0, 1.002, 1.001]
[1.29e-06, 2.92e-06, 8.36e-06, 1.52e-05]
</result>
Regards, Morton