python:任意顺序

在Oracle SQL中,有一个要按如下顺序排序的功能:

order by decode("carrot" = 2
               ,"banana" = 1
               ,"apple" = 3)

在python中实现它的最佳方法是什么？

我希望能够通过它的键来命令一个字典.而且该顺序不一定按字母顺序或任何顺序 - 我确定顺序.

使用key命名关键字参数sorted().

#set up the order you want the keys to appear here
order = ["banana", "carrot", "apple"]

# this uses the order list to sort the actual keys.
sorted(keys, key=order.index)

为了获得更高的性能list.index,您可以使用dict.get.

#this builds a dictionary to lookup the desired ordering
order = dict((key, idx) for idx, key in enumerate(["banana", "carrot", "apple"]))

# this uses the order dict to sort the actual keys.
sorted(keys, key=order.get)