Slicing vs .startswith

Bob Gailer bgailer at alum.rpi.edu
Mon Sep 22 17:57:41 CEST 2003


At 09:17 AM 9/22/2003, Shu-Hsien Sheu wrote:

>Hi,
>
>I have a question about the comparison of efficiency of string slicing and 
>using string.startswith.
>For example, which one of the following would be more efficient, or , 
>moreover, more pythonic?
>
>if aa[:3] == 'abc':
>
>vs
>
>if aa.startswith('abc'):

Here's one way to address this kind of question:

 >>> import time
 >>> def f():
...     st = time.time()
...     for i in range(500000):
...         if aa.startswith('abc'):pass
...     print time.time() - st
...
 >>> f()
1.01200008392
 >>> def f():
...     st = time.time()
...     for i in range(500000):
...         if aa[:3] == 'abc':pass
...     print time.time() - st
...
 >>> f()
1.01100003719

Bob Gailer
bgailer at alum.rpi.edu
303 442 2625
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