regular expression or parser ?

Kent Johnson kent at kentsjohnson.com
Tue Jan 3 14:21:59 CET 2006


Forced_Ambitions wrote:
> Hi,
> 
> I m a novice to python..I m stuck in a problem and need some help.
> 
> i m trying to extract data  between the line "start operation" and the
> line "stop operation"
> from a txt file. and then to fill it under different columns of an
> excel sheet.
> 

A simple stateful loop may be enough for the parsing part. Something 
like this:

f= open('data.txt')

try:
   while True:
     # Skip to the next start
     while f.next().strip() != 'start operation':
       continue

     # process lines
     while True:
       line = f.next().strip()
       if line == 'stop operation':
         break
       # process line

except StopIteration:
   pass


If you only have one block to process and you are confident it will 
always be present then the try / except and outer while loop are not needed.

If you can live with CSV output instead of XLS then see the csv module 
for the processing part.

Kent



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