Algorithm help per favore

[David Eppstein]

In article <bcshoh$kb8$1 at news.hccnet.nl>,
 anton at vredegoor.doge.nl (Anton Vredegoor) wrote:

> Output from a test run:
> 
> zipped  : 0.985 sec.
> ranged  : 0.425 sec.
> inplace : 0.206 sec.

Interesting.  When I try it, what I find is that zipped is usually but 
not always fastest, inplace is a little slower, and ranged is 
significantly slower -- data at end of message.

I tried also a simple generator based one but it didn't do better than 
the others:

def generate(L):
    return list(generator(L))

def generator(L):
   last = object()
   for x in L:
      if x != last:
         yield x
         last = x
    
The test data:

% python test.py
zipped  : 0.090 sec.
ranged  : 0.190 sec.
inplace : 0.090 sec.
generate: 0.120 sec.
% python test.py
zipped  : 0.090 sec.
ranged  : 0.180 sec.
inplace : 0.100 sec.
generate: 0.110 sec.
% python test.py
zipped  : 0.130 sec.
ranged  : 0.170 sec.
inplace : 0.100 sec.
generate: 0.110 sec.
% python test.py
zipped  : 0.070 sec.
ranged  : 0.150 sec.
inplace : 0.110 sec.
generate: 0.110 sec.
% python test.py
zipped  : 0.060 sec.
ranged  : 0.170 sec.
inplace : 0.090 sec.
generate: 0.090 sec.
% python test.py
zipped  : 0.040 sec.
ranged  : 0.170 sec.
inplace : 0.110 sec.
generate: 0.110 sec.
% python test.py
zipped  : 0.040 sec.
ranged  : 0.150 sec.
inplace : 0.100 sec.
generate: 0.100 sec.

-- 
David Eppstein                      http://www.ics.uci.edu/~eppstein/
Univ. of California, Irvine, School of Information & Computer Science