switch（封装）

#迭代器
class switch(object):
    def __init__(self,value):
        self.value=value
        self.fall=False
#迭代器方法
    def __iter__(self):
        yield self.match
        raise StopIteration
    def match(self,*args):
        if self.fall or not args:
            return True
        elif self.value in args:
            self.fall=True
            return True
        else:
            return False

调用

    v='ten'
    for case in switch(v):
        if case('one'):
            print 1
            break
        if case('ten'):
            print 10
            break