Remove item in a Python kiwi objectlist

I have an generic example from kiwi framework, my question is: How can I remove only a item from kiwi objectlist.

Thanks for the time!

import gtk

from kiwi.ui.objectlist import Column, ObjectList

class Fruit:
    def __init__(self, name, cost):
        self.name = name
        self.cost = cost

fruits = ObjectList([Column('name', data_type=str, editable=True,
                      expand=True),
               Column('cost', data_type=int, editable=True)])

for name, cost in [('Apple', 4),
                   ('Pineapple', 2),
                   ('Kiwi', 8),
                   ('Banana', 3),
                   ('Melon', 5)]:
    fruits.append(Fruit(name, cost))

window = gtk.Window()
window.connect('delete-event', gtk.main_quit)
window.set_title('Editable Fruit List')
window.set_size_request(230, 150)

#
## remove fruits
#
fruits开发者_Go百科.remove(Fruit('Pineapple', 4))  #error

window.add(fruits)
window.show_all()

gtk.main()

---

This code:

fruits.remove(Fruit('Pineapple', 4))  

produces this error:

Traceback (most recent call last):
...
    fruits.remove(Fruit('Pineapple', 4))  #error
  File "/tmp/kiwi/ui/objectlist.py", line 1651, in remove
    raise ValueError("instance %r is not in the list" % instance)
ValueError: instance <__main__.Fruit instance at 0x90066cc> is not in the list

which is an accurate description of the problem.

---

The instance argument to the .remove method of an ObjectList should be an object already in the list. Whenever you call Fruit(...) you get a new instance ever it its attributes are the same. If the instance is not in the list, a ValueError is raised (despite what the documentation says, apparently). For example:

new_fruit = Fruit('Pineapple', 4) # save this instance as new_fruit
fruits.append(new_fruit) # append this instance to the list
fruits.remove(new_fruit) # take this instance out ... success!

assert new_fruit is Fruit('Pineapple', 4) # False

So, in your existing code, you'll probably want to do something like this instead (replacing fruits.remove(Fruit('Pineapple', 4))):

fruits.remove(fruits[1])

Or, tie it to some ui action (double-click is just an example):

def remove_fruit(objlist, instance):
    objlist.remove(instance)

fruits.connect('double-click', remove_fruit)