Assessment:

Given
a = [1,2]<br /> b = [1,2]<br />
Which of the following expressions evaluates to False?

1. a == b
2. a[0] is 1
3. a is [1,2]
4. b == [1,2]

Exercise:

Read the following interpreter session and fill in the missing sections of code in the remove_exact function.

>>> class named_list(list):
def __init__(self,name,*args):
    super(named_list,self).__init__(*args)
    self.name = name

>>> fred = named_list('fred')
>>> fred.append(2)
>>> fred
[2]
>>> nameless = [2]
>>> nameless == fred
True
>>> list_of_lists =[fred,nameless]
>>> list_of_lists.remove(nameless)
>>> list_of_lists[0].name

Traceback (most recent call last):
File "<pyshell#84>", line 1, in
list_of_lists[0].name
AttributeError: 'list' object has no attribute 'name'

>>>def remove_exact(iterable, item):
for index,element in enumerate(iterable):
    if item __ element:
        _______.pop(_____)
        break

>>> list_of_lists =[fred,nameless]
>>> remove_exact(list_of_lists,nameless)
>>> list_of_lists[0].name
'fred'

Evaluation:

Which of the following code snippets always behaves the same as the expression a is not b?

1. a != b

2. [o for o in vars(a)] != [o for o in vars(b)]

3. not a == b

4. id(a) != id(b)

Bonus Question! What does this print in the standard intepreter? (Feel free to check this out yourself.)

>>> for x in range(300):
	if x is 290:
		print x
	if x is 5:
		print x