Python 列表的copy函数

a = [1,2,3]
b = a

a = [1,2,3]
b = a.copy()
b.append(4)
b  ->  [1,2,3,4]
a  ->  [1,2,3]

# coding:utf-8

old_list = ['python', 'django', 'flask']

new_list = old_list
new_list.append('tornado')
print(new_list)
print(old_list)
print(id(new_list), id(old_list))

old_list.remove('tornado')
print(new_list, old_list)

# old_list.clear()
# print(new_list, old_list)

del new_list
print(old_list)

old_list_copy = ['python', 'django', 'flask']
new_list_copy = old_list_copy.copy()

print(old_list_copy, new_list_copy)
new_list_copy.append('tornado_copy')
print(old_list_copy, new_list_copy)
print(id(old_list_copy), id(new_list_copy))