python的re在函数中编译之后，退出函数并不会立即被回收，下次会使用同样的re

python_re_compile_test.py

# -*- coding: utf-8 -*-
import re


def clean(string):
    re_strip = re.compile(r'(^\s+)|([\s:：]+$)')
    print id(re_strip)
    result = re_strip.sub('', string)
    return result

print clean("  test ,...")
print clean("\t  test ,...")


# output
4503430416
test ,...
4503430416
test ,...