OpenEuphoria

Re: Reading comma delimited .csv data files

• Posted by CChris <christian.cuvier at agric?lt?re.gouv.fr> Jan 18, 2008
• 591 views

JAYBEEDEE wrote:
> 
> 
> I'm having difficulty in getting Eu to read multiple column data tables
> created
> via Excel
> and saved as comma delimited text files.
> 
> I'm confused by the get(), gets(), getc() and value() commands.
> 
> Using gets() I have no problem in reading data in a single column, but if
> there
> are
> more than one, then gets() reads each row (line) as a single element.
> 
> For example, the csv file might be of the form:
> 
> Month,,
> 6,,
> 8,,
> 1988,,
> 
> 
> 2,6,8
> 5,12,25.7
> . 
> etc
> 
> Note 2 blank lines after 1988,, and blank cells in the grid as ,,
> 
> I would like to write the data into a sequence emulating 3 horizontal elements
> and n rows like
> 
> data{{}{}{}}  so that I can extract values using a statement like
> cell_value=data[row][col]
> 
> So far I'm defeated!  Any suggestions?

Euphoria doesn't have standard routines to read formatted input, contrary to
most other languages. Use the strtok library by Kat (in the archive) to split a
text string using commas as delimiters.

gets(your_file) will return say "8,," (a full line as a text string), and
applying the right function in strtok to this will split it to {"8","",""} (a
sequence of substrings some of which may be empty).

Now, if any of these substrings is known to represent a number, you can call
value() to perform the conversion.

FYI, win32lib has routines (w32split(), w32TextToNumber() and others) to do the
job.

A simple splitting function could be coded like this:

function split(sequence s)
  integer pos,prev_pos
  sequence result

  pos=find(',',s)
  if not pos then 
    return {s} -- no splitting took place
  end if 
  result={}
  prev_pos=0
  while pos do
    result=append(result,s[prev_pos+1..pos-1]) -- another substring
                                     -- substrings may well be empty
-- a sustring extends from prev delim+1 to next delim-1
    -- find next
    prev_pos=pos
    pos=find_from(',',s,prev_pos+1)
  end while
-- get tail substring and return the whole array
  return append(result,s[prev_pos+1..$]) 
end function

CChris