跳过-with-块的执行

如果您想要一个临时解决方案，它使用withhacks（特别是来自AnonymousBlocksInPython）的思想，那么它将起作用：

import sysimport inspectclass My_Context(object):    def __init__(self,mode=0):        """        if mode = 0, proceed as normal        if mode = 1, do not execute block        """        self.mode=mode    def __enter__(self):        if self.mode==1: print 'Met block-skipping criterion ...' # Do some magic sys.settrace(lambda *args, **keys: None) frame = inspect.currentframe(1) frame.f_trace = self.trace    def trace(self, frame, event, arg):        raise    def __exit__(self, type, value, traceback):        print 'Exiting context ...'        return True

比较以下内容：

with My_Context(mode=1):    print 'Executing block of pre ...'

与

with My_Context(mode=0):    print 'Executing block of pre ... '