From: Yaj Bhattacharya <yajnaval@...>
Date: 2009-03-14T03:02:51+09:00
Subject: Re: reading data files with headers and columns

Thanks very much Luc, here are a few follow up questions (complete
noob)

# here's the columns as arrays
  @column1 = []  # should this be @column1=[variable1] or just the
empty square brackets?
  <rest_of_columns>
  # open file in read mode (r)
  file = File.new("<your_filename", "r")
  # read each line one after another and process it
  file.each_line do |line|   # where do I specify how the header is to
be skipped, how many lines to
#be skipped or otherwise processed?
    # process as header if necessary
    # or
    # extract your variables in the line into an array
    array = line.split("<your_column_separator>") # I am guessing that
a space column separator
#would be " ", does it work with arbit number of multiple spaces
between the columns i.e. if the
#column width is variable but between two
# columns there are one or several spaces?
    # assign variable to column
    @column1 << array[0]
# if @column1=[variable1] comment in the second line of the above code
was not correct, then
#where do the variables get their names?
    # ... process other columns
  end


On Mar 13, 1:23 pm, Luc Traonmilin <luc.traonmi...@gmail.com> wrote:
> Yaj Bhattacharya a écrit :
>
>
>
> > Hello,
>
> > As a noob to Ruby, I need to read a data file with the first few lines
> > as header, then the rest of the file as columns of different variables
> > as arrays (in this case, 5 columns).
> > After reading in the variables, I want to calculate some operations
> > with each unique data field address (e.g. column3, row4), then write
> > out the file with headers and data in columns.
>
> > Could someone help with a few lines of basic code?
>
> > Thanks in advance
> > Yaj
>
> You could start with this basic piece of code (replace <tags> with your
> code):
>   # here's the columns as arrays
>   @column1 = []
>   <rest_of_columns>
>   # open file in read mode (r)
>   file = File.new("<your_filename", "r")
>   # read each line one after another and process it
>   file.each_line do |line|
>     # process as header if necessary
>     # or
>     # extract your variables in the line into an array
>     array = line.split("<your_column_separator>")
>     # assign variable to column
>     @column1 << array[0]
>     # ... process other columns
>   end
>
> Additionnally you can google "ruby array" and "ruby file", the API docs
> are well documented.
>
> Luc- Hide quoted text -
>
> - Show quoted text -