compare two lists in python 比较 list：set，sort，collection

master>views.py

# Create your views here.
def compare_2_list():
    old_list = ['A001', 'B002', 'C003']
    new_list = ['C003', 'A001', 'B002']

    s1 = set(old_list)
    s2 = set(new_list)

    if s1 == s2:
        print('s1 == s2')
        print(s1)
        print(s2)
    else:
        print('s1 != s2')

    if old_list == new_list:
        print('old_list == new_list')
    else:
        print('old_list != new_list')

    old_list.sort()
    new_list.sort()
    if old_list == new_list:
        print('old_list == new_list after sort')
    else:
        print('old_list != new_list after sort')

(venv) D:\PycharmProjects\djangoTutorial>python manage.py shell
Python 3.9.2 (tags/v3.9.2:1a79785, Feb 19 2021, 13:44:55) [MSC v.1928 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>> from master.views import compare_2_list
>>> compare_2_list()
s1 == s2
{'B002', 'A001', 'C003'}
{'B002', 'A001', 'C003'}
old_list != new_list
old_list == new_list after sort
['A001', 'B002', 'C003']
>>>

import collections

def compare_list_by_collection():
    old_list1 = ['A001', 'B002', 'C003', 'B002']
    old_list2 = ['A001', 'B002', 'C003']
    new_list = ['C003', 'A001', 'B002']

    if collections.Counter(old_list1) == collections.Counter(new_list):
        print("old_list1 and new_list are the same")
    else:
        print("old_list1 and new_list are not the same")

    if collections.Counter(old_list2) == collections.Counter(new_list):
        print("old_list2 and new_list are the same")
    else:
        print("old_list2 and new_list are not the same")

    print(collections.Counter(old_list1).items()) # dict_items([('A001', 1), ('B002', 2), ('C003', 1)])
    print(collections.Counter(old_list2).items()) # dict_items([('A001', 1), ('B002', 1), ('C003', 1)])
    print(collections.Counter(new_list).items())  # dict_items([('C003', 1), ('A001', 1), ('B002', 1)])
    print(collections.Counter(old_list1))  # Counter({'B002': 2, 'A001': 1, 'C003': 1})
    print(collections.Counter(old_list2))  # Counter({'A001': 1, 'B002': 1, 'C003': 1})
    print(collections.Counter(new_list))   # Counter({'C003': 1, 'A001': 1, 'B002': 1})

(venv) D:\PycharmProjects\djangoTutorial>python manage.py shell
Python 3.9.2 (tags/v3.9.2:1a79785, Feb 19 2021, 13:44:55) [MSC v.1928 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>> from master.views import compare_list_by_collection
>>> compare_list_by_collection()
old_list1 and new_list are not the same
old_list2 and new_list are the same
dict_items([('A001', 1), ('B002', 2), ('C003', 1)])
dict_items([('A001', 1), ('B002', 1), ('C003', 1)])
dict_items([('C003', 1), ('A001', 1), ('B002', 1)])
Counter({'B002': 2, 'A001': 1, 'C003': 1})
Counter({'A001': 1, 'B002': 1, 'C003': 1})
Counter({'C003': 1, 'A001': 1, 'B002': 1})
>>>