From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ian Barton <lists@manor-farm.org>
Subject: Re: My Python solution to generating unique Ids in headlines
Date: Thu, 05 Mar 2009 08:39:17 +0000
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References: <200903042320.n24NKDmD007471@mail11.syd.optusnet.com.au>
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> I settled on using a small Python script, since I am not
> a Lisp programmer.
> 
> 1.  I created a text file todononum.txt which contains
> the next number to use.
> 
> 2.  I created the following script to read this file, return the
> next available number formatted in a unique, easy to find string,
> for example [#310].
> 
> # script next_todo.py 
> import sys
> nextnum_file = "C:/charles/gtd/todonum.txt"
> 
> try:
>    f = open(nextnum_file, 'r')
> except IOError:
>    print "Unable to open %s. Program terminating." % nextnum_file
>    sys.exit(1)
> 
> val = int(f.readline()) + 1
> f.close()
> 
> of = open(nextnum_file, 'w')
> of.write("%d\n"  % val)
> of.close()
> 
> print "[#%s]" % val
> 
> 
Charles,

If you don't need human readable numbers, you could try something like 
the following to generate a hash:

import hashlib
from time import strftime

timestamp = strftime("%Y-%m-%d %H:%M:%S")
s = myorg_item + timestamp
myhash = hashlib.sha224(s).hexdigest()

This combines your org text with the current timestamp to generate a 
hash. Since it's unlikely that you will try to create a hash from two 
identical org items at the same moment in time, this should be unique.

Ian.