Object Oriented Python 简明教程

>>>
>>> # Any Empty List
>>> empty_list = []
>>>
>>> # A list of String
>>> str_list = ['Life', 'Is', 'Beautiful']
>>> # A list of Integers
>>> int_list = [1, 4, 5, 9, 18]
>>>
>>> #Mixed items list
>>> mixed_list = ['This', 9, 'is', 18, 45.9, 'a', 54, 'mixed', 99, 'list']
>>> # To print the list
>>>
>>> print(empty_list)
[]
>>> print(str_list)
['Life', 'Is', 'Beautiful']
>>> print(type(str_list))
<class 'list'>
>>> print(int_list)
[1, 4, 5, 9, 18]
>>> print(mixed_list)
['This', 9, 'is', 18, 45.9, 'a', 54, 'mixed', 99, 'list']

>>> tupl = ('Tuple','is', 'an','IMMUTABLE', 'list')
>>> tupl
('Tuple', 'is', 'an', 'IMMUTABLE', 'list')
>>> tupl[0]
'Tuple'
>>> tupl[-1]
'list'
>>> tupl[1:3]
('is', 'an')

>>> tupl
('Tuple', 'is', 'an', 'IMMUTABLE', 'list')
>>> tupl.append('new')
Traceback (most recent call last):
   File "<pyshell#148>", line 1, in <module>
      tupl.append('new')
AttributeError: 'tuple' object has no attribute 'append'
>>> tupl.remove('is')
Traceback (most recent call last):
   File "<pyshell#149>", line 1, in <module>
      tupl.remove('is')
AttributeError: 'tuple' object has no attribute 'remove'
>>> tupl.index('list')
4
>>> tupl.index('new')
Traceback (most recent call last):
   File "<pyshell#151>", line 1, in <module>
      tupl.index('new')
ValueError: tuple.index(x): x not in tuple
>>> "is" in tupl
True
>>> tupl.count('is')
1

>>> # empty dictionary
>>> my_dict = {}
>>>
>>> # dictionary with integer keys
>>> my_dict = { 1:'msft', 2: 'IT'}
>>>
>>> # dictionary with mixed keys
>>> my_dict = {'name': 'Aarav', 1: [ 2, 4, 10]}
>>>
>>> # using built-in function dict()
>>> my_dict = dict({1:'msft', 2:'IT'})
>>>
>>> # From sequence having each item as a pair
>>> my_dict = dict([(1,'msft'), (2,'IT')])
>>>
>>> # Accessing elements of a dictionary
>>> my_dict[1]
'msft'
>>> my_dict[2]
'IT'
>>> my_dict['IT']
Traceback (most recent call last):
   File "<pyshell#177>", line 1, in <module>
   my_dict['IT']
KeyError: 'IT'
>>>

>>> # Modifying a Dictionary
>>>
>>> my_dict
{1: 'msft', 2: 'IT'}
>>> my_dict[2] = 'Software'
>>> my_dict
{1: 'msft', 2: 'Software'}
>>>
>>> my_dict[3] = 'Microsoft Technologies'
>>> my_dict
{1: 'msft', 2: 'Software', 3: 'Microsoft Technologies'}

>>> # Mixing Data Types in a Dictionary
>>>
>>> my_dict
{1: 'msft', 2: 'Software', 3: 'Microsoft Technologies'}
>>> my_dict[4] = 'Operating System'
>>> my_dict
{1: 'msft', 2: 'Software', 3: 'Microsoft Technologies', 4: 'Operating System'}
>>> my_dict['Bill Gates'] = 'Owner'
>>> my_dict
{1: 'msft', 2: 'Software', 3: 'Microsoft Technologies', 4: 'Operating System',
'Bill Gates': 'Owner'}

>>> # Deleting Items from a Dictionary
>>>
>>> my_dict
{1: 'msft', 2: 'Software', 3: 'Microsoft Technologies', 4: 'Operating System',
'Bill Gates': 'Owner'}
>>>
>>> del my_dict['Bill Gates']
>>> my_dict
{1: 'msft', 2: 'Software', 3: 'Microsoft Technologies', 4: 'Operating System'}
>>>
>>> my_dict.clear()
>>> my_dict
{}

>>> #set of integers
>>> my_set = {1,2,4,8}
>>> print(my_set)
{8, 1, 2, 4}
>>>
>>> #set of mixed datatypes
>>> my_set = {1.0, "Hello World!", (2, 4, 6)}
>>> print(my_set)
{1.0, (2, 4, 6), 'Hello World!'}
>>>

>>> >>> #METHODS FOR SETS
>>>
>>> #add(x) Method
>>> topics = {'Python', 'Java', 'C#'}
>>> topics.add('C++')
>>> topics
{'C#', 'C++', 'Java', 'Python'}
>>>
>>> #union(s) Method, returns a union of two set.
>>> topics
{'C#', 'C++', 'Java', 'Python'}
>>> team = {'Developer', 'Content Writer', 'Editor','Tester'}
>>> group = topics.union(team)
>>> group
{'Tester', 'C#', 'Python', 'Editor', 'Developer', 'C++', 'Java', 'Content
Writer'}
>>> # intersets(s) method, returns an intersection of two sets
>>> inters = topics.intersection(team)
>>> inters
set()
>>>
>>> # difference(s) Method, returns a set containing all the elements of
invoking set but not of the second set.
>>>
>>> safe = topics.difference(team)
>>> safe
{'Python', 'C++', 'Java', 'C#'}
>>>
>>> diff = topics.difference(group)
>>> diff
set()
>>> #clear() Method, Empties the whole set.
>>> group.clear()
>>> group
set()
>>>

>>> # PYTHON SET OPERATIONS
>>>
>>> #Creating two sets
>>> set1 = set()
>>> set2 = set()
>>>
>>> # Adding elements to set
>>> for i in range(1,5):
   set1.add(i)
>>> for j in range(4,9):
   set2.add(j)
>>> set1
{1, 2, 3, 4}
>>> set2
{4, 5, 6, 7, 8}
>>>
>>> #Union of set1 and set2
>>> set3 = set1 | set2 # same as set1.union(set2)
>>> print('Union of set1 & set2: set3 = ', set3)
Union of set1 & set2: set3 = {1, 2, 3, 4, 5, 6, 7, 8}
>>>
>>> #Intersection of set1 & set2
>>> set4 = set1 & set2 # same as set1.intersection(set2)
>>> print('Intersection of set1 and set2: set4 = ', set4)
Intersection of set1 and set2: set4 = {4}
>>>
>>> # Checking relation between set3 and set4
>>> if set3 > set4: # set3.issuperset(set4)
   print('Set3 is superset of set4')
elif set3 < set4: #set3.issubset(set4)
   print('Set3 is subset of set4')
else: #set3 == set4
   print('Set 3 is same as set4')
Set3 is superset of set4
>>>
>>> # Difference between set3 and set4
>>> set5 = set3 - set4
>>> print('Elements in set3 and not in set4: set5 = ', set5)
Elements in set3 and not in set4: set5 = {1, 2, 3, 5, 6, 7, 8}
>>>
>>> # Check if set4 and set5 are disjoint sets
>>> if set4.isdisjoint(set5):
   print('Set4 and set5 have nothing in common\n')
Set4 and set5 have nothing in common
>>> # Removing all the values of set5
>>> set5.clear()
>>> set5 set()