Question

I want to do something like this:

class Foo(object):
    def __init__(self, name):
        self._name = name
        self._count = 0
    def getName(self):
        return self._name
    name = property(getName)
    def getCount(self):
        c = self._count
        self._count += 1
        return c
    count = property(getCount)
    def __repr__(self):
        return "Foo %(name)s count=%(count)d" % self.__dict__

but that doesn’t work because name and count are properties with getters.

Is there a way to fix this so I can use a format string with named arguments to cause getters to be called?

Answer 1

Just change it to not use self.__dict__. You have to access name and count as properties instead of trying to access them by the names that their properties are bound to:

class Foo(object):
    def __init__(self, name):
        self._name = name
        self._count = 0
    def getName(self):
        return self._name
    name = property(getName)
    def getCount(self):
        c = self._count
        self._count += 1
        return c
    count = property(getCount)
    def __repr__(self):
        return "Foo %s count=%d" % (self.name, self.count)

Then in use:

>>> f = Foo("name")
>>> repr(f)
'Foo name count=0'
>>> repr(f)
'Foo name count=1'
>>> repr(f)
'Foo name count=2'

EDIT: You can still use named formatting but you have to change your approach since you can’t access the properties via the names you want:

def __repr__(self):
    return "Foo %(name)s count=%(count)d" % {'name': self.name, 'count': self.count}

This could be better if you repeat things and/or have a lot of things, but it is a bit goofy.