python内置类型的比较顺序

Question

I'm looking for a good set of sentinel values, eg experimentally:

[] > "sdfasfg" > ()

And this seems to be documented:

CPython implementation detail: Objects of different types except numbers are ordered by their type names; objects of the same types that don't support proper comparison are ordered by their address. reference

In the same fashion,

object() < str()

The "largest" builtin type seems to be unicode , what can I use as a "right" sentinel value for comparison with unicode types? That is a value that's larger than any unicode string?

Is comparison order of instances of built-in types really well defined in Python?

Answer 1

The comparison of arbitrary objects is called "rich comarisons". There is some documentation here , and here .

If you are working with Python 3, then check this out . Relevant quote from this source:

Having both the rich comparison methods and the __cmp__() method violates the principle that there should be only one obvious way to do it, so in Python 3 the support for __cmp__() has been removed. For Python 3 you therefore must implement all of the rich comparison operators if you want your objects to be comparable.