ASCII delimited files

William King wjk at wjk.mv.com
Tue Nov 16 03:56:47 CET 1999


Roger Irwin wrote:

> Is there any function or module available for parsing ASCII delimited files,
> before I go and re-invent the wheel writing my own.
>
> BTW, I know it is simple to do, but I was thinking along the lines that a
> 'standard' could easily be substituted for a C version for large files.

#Was reading news and noted this discussion#on comma-delimited files so I
thought that maybe as a
#programming/python newbie I could try and contribute.

#CVT - comma delimited file input function
#read in lines of input - 1 line =='s 1 record
#pass line to function and return a list of fields
#double quotes are supposed to be in pairs (Beware cause some
#will backslash double quotes and put them in a data field) or
#data could be invalid because of a missing "
#may want to re.compile(pattern) and substitute this combo
#to something else.
#also note that it is also not uncommon to see a tab or comma
#delimited file with other character delimiters in a field
#ie.     data,"data,data",data|data|data|data
#does seem a bit 'python_awkish' -- I apologize



from string import split

def comma_Cvt( aString ):                           #function to read cvt string

     stop_N_go = 0                                        #create a guardian
     newstr = ""                                             #new string to
create
     for s_Char in aString:                           #for loop for chars in
aString
          if ( s_Char == '\"' ):                            #Look for " in
s_Char (character but really a string)
               if ( stop_N_go == 0 ):                  #Set guardian to 1 or 0
                    stop_N_go = 1
                    continue                                  #if 1st " guardian
to 1; cont.
               else:
                    stop_N_go = 0                         #if 2nd " guardian to
2; cont.
                    continue
          if ( s_Char == ','):                              #if a , as char
               if ( stop_N_go == 0 ):                     #if guardian is 0 set
the char
                    s_Char = '~~~'                             #to be ~~~  or
some other combo
                     newstr = newstr + s_Char           #build a newstring
     return split(newstr,'~~~')  #return list broken up for more


I tried this out on a couple of lines to test and see if it works -- seems too

Anyhow, just an idea -- while I learn I might as well take a stab at stuff and
sorry
havn't learned objects yet ...... Oh yeah, thanks to all who have been kind
enough to
respond to some of my NEWBIE questions.

wjk





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