>>> num1 = {}
>>> type(num1)
<class 'dict'>
>>>
>>> num2 = {1, 2, 3}
>>> type(num2)
<class 'set'>
>>>
>>> num1 = [1, 2, 3, 4, 3, 1]
>>> tmp = []
>>> for x in num1:
if x not in tmp:
tmp.append(x)
>>> tmp
[1, 2, 3, 4]
>>> num1 = [1, 2, 3, 4, 5, 5, 3, 1, 0]
>>> num1 = list(set(num1))
>>> num1
[0, 1, 2, 3, 4, 5]
>>>
-----------------
>>> num2 = [1, 2, 3, 4, 5]
>>> 1 in num2
True
>>> "1" in num2
False
>>> num2.add(6)
Traceback (most recent call last):
File "<pyshell#158>", line 1, in <module>
num2.add(6)
AttributeError: 'list' object has no attribute 'add'
>>> type(num2)
<class 'list'>
>>> num3 = {1, 2, 3}
>>> num3.add(4)
>>> num3
{1, 2, 3, 4}
>>> num3.remove(2)
>>> num3
{1, 3, 4}
---------------------------------
>>> num4 = frozenset([1, 2, 3, 4])
>>> num4.add(0)
Traceback (most recent call last):
File "<pyshell#174>", line 1, in <module>
num4.add(0)
AttributeError: 'frozenset' object has no attribute 'add'
>>>