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其他语言中，switch语句大概是这样的

switch (var) 
    {
     
        case value1: do_some_stuff1(); 
        case value2: do_some_stuff2(); 
        ... 
        case valueN: do_some_stuffN(); 
        default: do_default_stuff(); 
    } 
    
    
     
  而python本身没有switch语句，解决方法有以下3种: A.使用dictionary values = {
             value1: do_some_stuff1,            value2: do_some_stuff2,            ...            valueN: do_some_stuffN,          } values.get(var, do_default_stuff)() B.使用lambda result = {
     'a': lambda x: x * 5,   'b': lambda x: x + 7,   'c': lambda x: x - 2 }[value](x) C.提供了一个类 switch 来实现其他语言中switch的功能    
       
    
     
     # This class provides the functionality we want. You only need to look at 
     # this if you want to know how this works. It only needs to be defined 
     # once, no need to muck around with its internals. 
     class switch(object): 
         def __init__(self, value): 
             self.value = value 
             self.fall = False 
     
         def __iter__(self): 
             """Return the match method once, then stop""" 
             yield self.match 
             raise StopIteration 
     
         def match(self, *args): 
             """Indicate whether or not to enter a case suite""" 
             if self.fall or not args: 
                 return True 
             elif self.value in args: # changed for v1.5, see below 
                 self.fall = True 
                 return True 
             else: 
                 return False 
     
     # The following example is pretty much the exact use-case of a dictionary, 
     # but is included for its simplicity. Note that you can include statements 
     # in each suite. 
     v = 'ten' 
     for case in switch(v): 
         if case('one'): 
             print 1 
             break 
         if case('two'): 
             print 2 
             break 
         if case('ten'): 
             print 10 
             break 
         if case('eleven'): 
             print 11 
             break 
         if case(): # default, could also just omit condition or 'if True' 
             print "something else!" 
             # No need to break here, it'll stop anyway

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