相关疑难解决方法(0)

这是我的代码:

f = open('text/a.log', 'wb')
f.write('hahaha')
f.close()

并且在不存在时不创建新文件

这该怎么做 ,

谢谢

更新

class MyThread(threading.Thread):
    def run(self):
        f = open('a.log', 'w')
        f.write('hahaha')
        f.close()

错误是:

Traceback (most recent call last):
  File "D:\Python25\lib\threading.py", line 486, in __bootstrap_inner
    self.run()
  File "D:\zjm_code\helloworld\views.py", line 15, in run
    f = open('a.log', 'w')
  File "d:\Program Files\Google\google_appengine\google\appengine\tools\dev_appserver.py", line 1188, in __init__
    raise IOError('invalid mode: %s' % mode)
IOError: invalid mode: w