threading a 10 lines out of a file

alex goretoy aleksandr.goretoy at gmail.com
Mon Jan 5 08:22:33 CET 2009


I've found a great example on how to do threads. It compares a ping program
in regular for loop and with threaded for loop. The link is below if anyone
is interested.

http://www.wellho.net/solutions/python-python-threads-a-first-example.html

I hope my eagerness to post doesn't annoy anyone. I like to get as much info
from as many places as possible and compare. This way I think I may have a
better solution for a problem. Plus people that Google will find this post
or any words in it. Any more information on threading a for loop would be
greatly appreciated. TIA

-Alex Goretoy
http://www.alexgoretoy.com



On Mon, Jan 5, 2009 at 6:00 AM, alex goretoy <aleksandr.goretoy at gmail.com>wrote:

> Hello All,
>
> I have a question. I'm not sure exactly as how to explain it in any other
> way then the way I will explain it. So I'm sorry if it's hard to understand
> exactly what it is I'm trying to do. Maybe not. Anyway. Here goes.
>
> Lets say I have a file that looks like this.
>
> id,name,desc,test
> 123,abc,testing is fun,yeah baby
> 456,qwe,python makes if funner, yeah baby
> 789,zxc,this is another line in this file, yeah baby
> ...
> ...
>
> This file can have an unknown amount of lines in it. It can be 700,400 or
> even 7,000.
> I do this to read the file:
>
>         try:
>             reader = csv.reader(file(filename, "rb"))
>             try:
>                 header = reader.next()
>                 self.buffer = list(reader) # total = len(self.buffer)
>                 self.bufferp= [dict(zip(header,line)) for line in
> self.buffer]
>                 self.header = header
>                 #for row in reader:
>                     #self.buffer.append(row)
>                     #s,a=[],{}
>
>                     #for j in range(len(self.buffer[0])):
>                         #a[self.buffer[0][j]]=row[j]
>                     #self.bufferp.append(a)
>                     #i+=1
>                 #self.total = i-1
>             except csv.Error, e:
>                 sys.exit('file %s, line %d: %s' % (filename,
> reader.line_num, e))
>         except IOError, e:
>             sys.exit('file %s, IOError: %s' % (filename, e))
>
> What I am currently doing is looping over this file, performing a function
> for every line. This function isbeing called from this class __init__(),
>
> def loop_lines(self):
>
>         for k in range(len(self.buffer)): #for every line in csv file
>             self.line=self.buffer[k]
>             self.some_function(self.line)
>
>
> Now, for my question. Is it possible for me to thread this scenario
> somehow?
>
> So that I can set a variable that says how many lines to work on at the
> same time?
>
> lets say 10 lines at a time, once it finishes some it moves on to the next
> ones that are not in the thread pool or something to that nature. Always
> making sure that it works on 10 at the same time.
>
> How would I achieve something like this in my program? Can someone please
> recommend something for me. I would greatly appreciate. My program would
> appreciate it too, seeing as it will be multi-threaded :) Thank you for your
> help.
>
> -Alex Goretoy
> http://www.alexgoretoy.com
>
>
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