On May 10, 2:25 am, Stefan Behnel <stefan...@behnel.de> wrote: > Stefan Behnel, 10.05.2010 08:54: > > > > > > > dasacc22, 08.05.2010 19:19: > >> This is a simple question. I'm looking for the fastest way to > >> calculate the leading whitespace (as a string, ie ' '). > > > Here is an (untested) Cython 0.13 solution: > > > from cpython.unicode cimport Py_UNICODE_ISSPACE > > > def leading_whitespace(unicode ustring): > > cdef Py_ssize_t i > > cdef Py_UNICODE uchar > > > for i, uchar in enumerate(ustring): > > if not Py_UNICODE_ISSPACE(uchar): > > return ustring[:i] > > return ustring > > > Cython compiles this to the obvious C code, so this should be impossible > > to beat in plain Python code. > > ... and it is. For a simple string like > > u = u" abcdefg" + u"fsdf"*20 > > timeit gives me this for "s=u.lstrip(); u[:-len(s)]": > > 1000000 loops, best of 3: 0.404 usec per loop > > and this for "leading_whitespace(u)": > > 10000000 loops, best of 3: 0.0901 usec per loop > > It's closer for the extreme case of an all whitespace string like " "*60, > where I get this for the lstrip variant: > > 1000000 loops, best of 3: 0.277 usec per loop > > and this for the Cython code: > > 10000000 loops, best of 3: 0.177 usec per loop > > But I doubt that this is the main use case of the OP. > > Stefan
indeed, actually ive been going back and forth on the idea to use cython for some more intensive portions. That bit of code looks really simple so I think I'll give cython a shot. Only deal is I need to be able to use w/e the latest cython is available via easy_install, but this should prove an interesting experience. -- http://mail.python.org/mailman/listinfo/python-list
