[Tutor] processing multi entry logs

[Alan Gauld]

>I have a log file. Essentially the file has 2 important entries for
> each process id. One when the process starts with an id and a 
> another
> piece of data. the second is when the process finishes, with the
> result also with the process id.

> I can't think of an efficient way to store the data from the first
> entry.

This sounds like a job for a dictionary based on process Id.
You can store a tuple of start/stop times and key it by pid.

In pseudo code:

for line in logfile:
    pid,event,time = parseData(line)
    if event == start
        processes[pid] = [time,0]
    elif event == stop:
        processes[pid][1] = time

That throws all other events away and leaves you a dictionary
holding start and stop times per process id.

> Keep processing line by line and check against the partially 
> recorded
> ids?

Thats what I've done yes.

HTH,

Alan Gauld
Author of the Learn to Program web site
http://www.freenetpages.co.uk/hp/alan.gauld