From: "juan pedro meriño" <juapdiaz@...>
Date: 2007-06-29T22:57:12+09:00
Subject: Re: newbie questions on processing numerical data from text files

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How i create array under ruby?
for example need create a vector type array


2007/6/29, Axel Etzold <AEtzold@gmx.de>:
>
> Dear Baptiste,
>
> welcome to Ruby!
>
> > Here is my practical problem:
> >
> > - I open a text file,
>
> (... which already exists):
>
> interesting_text=3DIO.readlines(file_name)
>
> gives you an Array, with the lines as entries
>
>
>
> >locate a line according to some keyword
>
>
> interesting_text.delete_if{|line|  /(r|R)uby/.match=3D=3Dnil}
>
> removes all lines that don't contain the string Ruby or ruby,
>
> > or line number,
>
>
> interesting_text[line_number]  # (start counting at 0)
>
>
>
> > and change a value
> old_value=3D1.2
> new_value=3D2.4
>
> interesting_text.sub!(value.to_s,new_value.to_s)
>
> > - I run a fortran program
>
> result=3D`...`  where ... is the system command you use to start
> your fortran program,
>
>
> > - I read a text file (output of this program), extract several
> > numerical values
>
> You can do the reading with IO.readlines, the extraction with a
> Regexp,
>
> > and export them in a two column text file
>
> and this via
>
> f=3DFile.new("my_result_file.txt","w")
> f.puts formatted_text
> f.close
>
>
> > Here is the content of "sampleTextFile.dat":
> >
> > > this is a meaningless line
> > > another one
> > >
> > > maybe this line acts as a keyword for the following data
> > >
>
> I don't know how to interpret the values in brackets in the
> following line:
>
> > > 1 3.1 (415, 19e-12)
>
> If you read the file in via IO.readlines, it's a String element
> of an Array, say line=3D"1 3.1 (415, 19e-12)"
> so you could do:
>
> numbers=3Dline.gsub(/[\(,\)]/,'').split  <=3D removes brackets an gives
> a four element Array (of Strings), which you can turn ito numbers via
> eval
>
> number_array=3Dline.gsub(/[\(,\)]/,'').split.map{|x| eval(x)}
>
> Some other approach might be to assign variable names to each element
> in a line
>
> vars_names=3D['a','b','c','d']
> array_of_hashes=3D[]
> lines.each{|line|
>   vals_line=3Dline.gsub(/[\(,\)]/,'').split.map{|x| eval(x)}
>   tmp=3D{}
>   vars_names.each_with_index{|var_name,index|
>         tmp.store(var_name,vals_line[index])
>   }
>   array_of_hashes<<tmp
> }
>
> will give something like:
>
> [{"a"=3D>1,"b"=3D>3.1,"c"=3D>415,"d"=3D>19e-12},...]
>
>
>
> Best regards,
>
> Axel
> --
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>
>


--=20
Juan Pedro Meri=F1o Diaz
Ing de Sistema CURN

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