Perl speed vs. Python speed

[Fredrik Lundh]

Tom Culliton" <culliton at clark.net> wrote:
> The "new" Python re module needs to be optimized and possibly pushed
> into C code, the older regex module is about twice as fast.

if everything goes according to plan, 're' (and possibly also
'regex') will be replaced by a new unicode-aware engine in
1.6.  I've attached some (somewhat outdated) benchmarks.

note that 'regex' is faster than 're' only if you apply simple
regular expressions many times.  if you can reorganize the
code to use a single regular expression on a larger string,
're' beats the hell out of 'regex'.  ...and if you make things
complicated enough, 'regex' stops working... (but as usual,
some people prefer to get the wrong answer quickly ;-)

</F>

          0     5    50   250  1000  5000 25000
----- ----- ----- ----- ----- ----- ----- -----
search for Python|Perl in Perl ->
sre8  0.007 0.008 0.010 0.010 0.020 0.073 0.349
sre16 0.007 0.007 0.008 0.010 0.020 0.075 0.353
re    0.097 0.097 0.101 0.103 0.118 0.175 0.480
regex 0.007 0.007 0.009 0.020 0.059 0.271 1.320

search for (Python|Perl) in Perl ->
sre8  0.007 0.007 0.007 0.010 0.020 0.074 0.344
sre16 0.007 0.007 0.008 0.010 0.020 0.074 0.347
re    0.110 0.104 0.111 0.115 0.125 0.184 0.559
regex 0.006 0.006 0.009 0.019 0.057 0.285 1.432

search for Python in Python ->
sre8  0.007 0.007 0.007 0.011 0.021 0.072 0.387
sre16 0.007 0.007 0.008 0.010 0.022 0.082 0.365
re    0.107 0.097 0.105 0.102 0.118 0.175 0.511
regex 0.009 0.008 0.010 0.018 0.036 0.139 0.708

search for .*Python in Python ->
sre8  0.008 0.007 0.008 0.011 0.021 0.079 0.379
sre16 0.008 0.008 0.008 0.011 0.022 0.075 0.402
re    0.102 0.108 0.119 0.183 0.400 1.545 7.284
regex 0.013 0.019 0.072 0.318 1.231 8.035 45.366

search for .*Python.* in Python ->
sre8  0.008 0.008 0.008 0.011 0.021 0.080 0.383
sre16 0.008 0.008 0.008 0.011 0.021 0.079 0.395
re    0.103 0.108 0.119 0.184 0.418 1.685 8.378
regex 0.013 0.020 0.073 0.326 1.264 9.961 46.511

search for .*(Python) in Python ->
sre8  0.007 0.008 0.008 0.011 0.021 0.077 0.378
sre16 0.007 0.008 0.008 0.011 0.021 0.077 0.444
re    0.108 0.107 0.134 0.240 0.637 2.765 13.395
regex 0.026 0.112 3.820 87.322 ...

search for .*P.*y.*t.*h.*o.*n.* in Python ->
sre8  0.010 0.010 0.014 0.031 0.093 0.419 2.212
sre16 0.010 0.011 0.014 0.030 0.093 0.419 2.292
re    0.112 0.121 0.195 0.521 1.747 8.298 40.877
regex 0.026 0.048 0.248 1.148 4.550 24.720 ...

(searching for the given patterns in strings padded
with blanks on both sides.  sre8 is the new python
1.6 engine on 8-bit strings, sre16 is the same engine
using unicode)

reg·u·lar
1: belonging to a religious order