OpenEuphoria

Re: Reading comma delimited .csv data files

• Posted by JAYBEEDEE <daviesjb at liv??c.uk> Jan 19, 2008
• 796 views

CChris wrote:
> 
> 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:
> }}}
<eucode>
> 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
> </eucode>
{{{

> CChris
Thanks, Chris

I had tried using find and find_from to slice up the strings but always got a
zero result.
I note that you included the comma in single quotes ',' whereas I used double
quotes ",".  Was this where I went wrong? There doesn't seem to be anything in
the Euphoria Manual
about this distinction.

Your code looks is if it should do the job, but I haven't tried it yet.

Incidentally - is there an index or database of "include" files and the
procedures they contain?
Searching the Archives comes up with a lot of chat, and files with unhelpful
titles
such as "Routines I wish had been included with Euphoria", but no indication as
to what they contain.
Makes life hard for us newbies.