局部变量'sresult'在赋值前被引用

Question

我在使用PP的时候遇到了很多问题。我现在用的是python2.6和pp 1.6.0 rc3。下面是我用的测试代码：

import pp
nodes=('mosura02','mosura03','mosura04','mosura05','mosura06',
       'mosura09','mosura10','mosura11','mosura12')

def pptester():
        js=pp.Server(ppservers=nodes)
        tmp=[]
        for i in range(200):
                tmp.append(js.submit(ppworktest,(),(),('os',)))
        return tmp

def ppworktest():
        return os.system("uname -a")

运行后得到的结果是：

In [10]: Exception in thread run_local:
Traceback (most recent call last):
  File "/usr/lib64/python2.6/threading.py", line 525, in __bootstrap_inner
    self.run()
  File "/usr/lib64/python2.6/threading.py", line 477, in run
    self.__target(*self.__args, **self.__kwargs)
  File "/home/wkerzend/python_coala/lib/python2.6/site-packages/pp.py", line 751, in _run_local
    job.finalize(sresult)
UnboundLocalError: local variable 'sresult' referenced before assignment

Exception in thread run_local:
Traceback (most recent call last):
  File "/usr/lib64/python2.6/threading.py", line 525, in __bootstrap_inner
    self.run()
  File "/usr/lib64/python2.6/threading.py", line 477, in run
    self.__target(*self.__args, **self.__kwargs)
  File "/home/wkerzend/python_coala/lib/python2.6/site-packages/pp.py", line 751, in _run_local
    job.finalize(sresult)
UnboundLocalError: local variable 'sresult' referenced before assignment

Exception in thread run_local:
Traceback (most recent call last):
  File "/usr/lib64/python2.6/threading.py", line 525, in __bootstrap_inner
    self.run()
  File "/usr/lib64/python2.6/threading.py", line 477, in run
    self.__target(*self.__args, **self.__kwargs)
  File "/home/wkerzend/python_coala/lib/python2.6/site-packages/pp.py", line 751, in _run_local
    job.finalize(sresult)
UnboundLocalError: local variable 'sresult' referenced before assignment

Exception in thread run_local:
Traceback (most recent call last):
  File "/usr/lib64/python2.6/threading.py", line 525, in __bootstrap_inner
    self.run()
  File "/usr/lib64/python2.6/threading.py", line 477, in run
    self.__target(*self.__args, **self.__kwargs)
  File "/home/wkerzend/python_coala/lib/python2.6/site-packages/pp.py", line 751, in _run_local
    job.finalize(sresult)
UnboundLocalError: local variable 'sresult' referenced before assignment

非常感谢任何帮助。

Answer 1

这是pp库里的一个错误。你可以自己修复它，或者等着别人修复。

Answer 2

我看不懂你的代码，因为格式不太对，但我可以告诉你你遇到的具体问题：你在一个函数里想要修改一个叫“sresult”的全局变量，但你没有在函数开头加上这一行：

global sresult

如果你不声明一个变量是全局的，Python会认为它是这个函数内部的局部变量。如果你在函数里试图给它赋值，Python就会报错，提示你还没有“绑定这个局部变量”（也就是还没有给它赋值或者设定一个值）。