fork(3) download
copy 
  1. #!/usr/bin/env python
  2. # -*- coding: utf-8 -*-
  3. import re
  4.  
  5. def lreplace(s, old, new):
  6.     """Return a copy of string `s` with leading occurrences of
  7.     substring `old` replaced by `new`.
  8.  
  9.     >>> lreplace('abcabcdefabc', 'abc', 'X')
  10.     'XXdefabc'
  11.     >>> lreplace('_abc', 'abc', 'X')
  12.     '_abc'
  13.     >>> print lreplace('☃☃_[☃]_☃', '☃', 'SM')
  14.     SMSM_[☃]_☃
  15.     """
  16.     return re.sub(r'^(?:%s)+' % re.escape(old),
  17.                   lambda m: new * (m.end() // len(old)),
  18.                   s)
  19.  
  20. def replaceLeadingString(string, old, new = ''):
  21.     # http://stackoverflow.com/q/4649997
  22.     n = 0
  23.     o = 0
  24.     s = len(old)
  25.  
  26.     while string.startswith(old, o):
  27.         n += 1
  28.         o += s
  29.  
  30.     return new * n + string[o:]
  31.  
  32. #from profilestats import profile
  33. #@profile
  34. def test(n):
  35.     for _ in xrange(n):
  36.         old, new = 'префикс', 'abc'
  37.         for s in [old*2 +'остаток',
  38.                   'no'+old,
  39.                   old,
  40.                   old*2,
  41.                   new+new,
  42.                   'xx\n'+old,
  43.                   ]:
  44.             args = s, old, new
  45.             assert lreplace(*args) == replaceLeadingString(*args)
  46.  
  47. if __name__=="__main__":
  48.     import cProfile
  49.     cProfile.run('test(10**4)')
  50.  
  51.  
Success #stdin #stdout 2.27s 6724KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
         860332 function calls (860325 primitive calls) in 2.255 CPU seconds

   Ordered by: standard name

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
        1    0.000    0.000    2.255    2.255 <string>:1(<module>)
    30000    0.057    0.000    0.083    0.000 prog.py:17(<lambda>)
    60000    0.184    0.000    0.269    0.000 prog.py:20(replaceLeadingString)
        1    0.171    0.171    2.255    2.255 prog.py:34(test)
    60000    0.224    0.000    1.815    0.000 prog.py:5(lreplace)
    60000    0.112    0.000    0.567    0.000 re.py:144(sub)
    60000    0.890    0.000    1.024    0.000 re.py:206(escape)
    60000    0.108    0.000    0.163    0.000 re.py:229(_compile)
        1    0.000    0.000    0.000    0.000 sre_compile.py:360(_simple)
        1    0.000    0.000    0.000    0.000 sre_compile.py:367(_compile_info)
      3/1    0.000    0.000    0.000    0.000 sre_compile.py:38(_compile)
        2    0.000    0.000    0.000    0.000 sre_compile.py:480(isstring)
        1    0.000    0.000    0.000    0.000 sre_compile.py:486(_code)
        1    0.000    0.000    0.001    0.001 sre_compile.py:501(compile)
        4    0.000    0.000    0.000    0.000 sre_parse.py:132(__len__)
       20    0.000    0.000    0.000    0.000 sre_parse.py:136(__getitem__)
        1    0.000    0.000    0.000    0.000 sre_parse.py:140(__setitem__)
       16    0.000    0.000    0.000    0.000 sre_parse.py:144(append)
      4/2    0.000    0.000    0.000    0.000 sre_parse.py:146(getwidth)
        1    0.000    0.000    0.000    0.000 sre_parse.py:184(__init__)
       23    0.000    0.000    0.000    0.000 sre_parse.py:188(__next)
        8    0.000    0.000    0.000    0.000 sre_parse.py:201(match)
       19    0.000    0.000    0.000    0.000 sre_parse.py:207(get)
       14    0.000    0.000    0.000    0.000 sre_parse.py:263(_escape)
      2/1    0.000    0.000    0.000    0.000 sre_parse.py:307(_parse_sub)
      2/1    0.000    0.000    0.000    0.000 sre_parse.py:385(_parse)
        1    0.000    0.000    0.000    0.000 sre_parse.py:669(parse)
        1    0.000    0.000    0.000    0.000 sre_parse.py:73(__init__)
        3    0.000    0.000    0.000    0.000 sre_parse.py:96(__init__)
        1    0.000    0.000    0.000    0.000 {_sre.compile}
    30000    0.015    0.000    0.015    0.000 {built-in method end}
    60000    0.210    0.000    0.293    0.000 {built-in method sub}
       23    0.000    0.000    0.000    0.000 {isinstance}
150069/150068    0.055    0.000    0.055    0.000 {len}
       59    0.000    0.000    0.000    0.000 {method 'append' of 'list' objects}
        1    0.000    0.000    0.000    0.000 {method 'disable' of '_lsprof.Profiler' objects}
    60028    0.053    0.000    0.053    0.000 {method 'get' of 'dict' objects}
        1    0.000    0.000    0.000    0.000 {method 'items' of 'dict' objects}
    60000    0.060    0.000    0.060    0.000 {method 'join' of 'str' objects}
   110000    0.064    0.000    0.064    0.000 {method 'startswith' of 'str' objects}
        6    0.000    0.000    0.000    0.000 {min}
       14    0.000    0.000    0.000    0.000 {ord}
    60000    0.051    0.000    0.051    0.000 {range}
https://ideone.com/A53co
language:
Python (cpython 2.7.16)
created:
13 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!