python 中switch的实现

                                There is currently no switch statement in Python. Often this is
not a problem and can be handled through a series of
if-elif-else statements. However, there are many
other ways to handle the deficiency. The following example shows how to create a
simple switch statement in Python:
               
               
                def a(s):
    print s
def switch(ch):
    try:
      {'1': lambda : a("one"),
       '2': lambda : a("two"),
      '3': lambda : a("three"),
       'a': lambda : a("Letter a")
      }[ch]()
    except KeyError:
      a("Key not Found")
eg:
>>switch('1')
one
>>switch('a')
Letter a
>>switch('b')
Key not Found