next line (data parsing)

[George Sakkis]

On Jan 17, 12:01 am, Scott David Daniels <Scott.Dani... at Acm.Org>
wrote:
> robleac... at gmail.com wrote:
> > Hi there,
> > I'm struggling to find a sensible way to process a large chuck of
> > data--line by line, but also having the ability to move to subsequent
> > 'next' lines within a for loop. I was hoping someone would be willing
> > to share some insights to help point me in the right direction. This
> > is not a file, so any file modules or methods available for files
> > parsing wouldn't apply.
>
> > I can iterate over each line by setting a for loop on the data object;
> > no problem. But basically my intension is to locate the line "Schedule
> > HOST" and progressively move on to the 'next' line, parsing out the
> > pieces I care about, until I then hit "Total", then I resume to the
> > start of the for loop which locates the next "Schedule HOST".
>
> if you can do:
>
>      for line in whatever:
>          ...
>
> then you can do:
>
>      source = iter(whatever)
>      for intro in source:
>          if intro.startswith('Schedule '):
>              for line in source:
>                  if line.startswith('Total'):
>                      break
>                  process(intro, line)
>
> --Scott David Daniels
> Scott.Dani... at Acm.Org

Or if you use this pattern often, you may extract it to a general
grouping function such as http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/521877:

import re

for line in iterblocks(source,
                                start = lambda line:
line.startswith('Schedule HOST'),
                                end = lambda line: re.search(r'^
\s*Total',line),
                                skip_delim=False):
    process(line)


George