python深浅copy,is,id

1. 看代码写结果

   v1 = [1,2,3,4,5]
   v2 = [v1,v1,v1]
   
   v1.append(6)
   print(v1)
   print(v2)
   

   v1 = [1,2,3,4,5,6]
   v2 = [[1,2,3,4,5,6],[1,2,3,4,5,6],[1,2,3,4,5,6]]
   

2. 看代码写结果

   v1 = [1,2,3,4,5]
   v2 = [v1,v1,v1]
   
   v2[1][0] = 111
   v2[2][0] = 222
   print(v1)
   print(v2)
   

   结果：

   v1 = [222,2,3,4,5]
   v2 = [[222,2,3,4,5], [222,2,3,4,5], [222,2,3,4,5]]
   

3. 看代码写结果，并解释每一步的流程。

   v1 = [1,2,3,4,5,6,7,8,9]
   v2 = {}
   
   for item in v1:
       if item < 6:
           continue
       if ‘k1‘ in v2:
           v2[‘k1‘].append(item)
   	else:
           v2[‘k1‘] = [item ]
   print(v2)
   

   结果：

   v1 = [1, 2, 3, 4, 5, 6, 7, 8, 9]
   v2 = {}  # 建立空字典
   
   for item in v1: # 遍历列表v1
       if item < 6: # 如果列表元素小于6时中止继续下次循环
           continue
       if ‘k1‘ in v2: # item大于等于6时，如果‘k1‘在v2字典中
           v2[‘k1‘].append(item) # ‘k1‘的键值追加item
       else:
           v2[‘k1‘] = [item]  # 否则直接增加键值对：‘k1‘:item
   print(v2)
   
   # v2 = {‘k1‘:[6,7,8,9}
   

4. 简述深浅拷贝？

5. 看代码写结果

   import copy
   
   v1 = "alex"
   v2 = copy.copy(v1)
   v3 = copy.deepcopy(v1)
   
   print(v1 is v2)
   print(v1 is v3)
   

   结果：

   True
   True
   

6. 看代码写结果

   import copy
   
   v1 = [1,2,3,4,5]
   v2 = copy.copy(v1)
   v3 = copy.deepcopy(v1)
   
   print(v1 is v2)
   print(v1 is v3)
   

   False
   False
   
   

7. 看代码写结果

   import copy
   
   v1 = [1,2,3,4,5]
   
   v2 = copy.copy(v1)
   v3 = copy.deepcopy(v1)
   
   print(v1[0] is v2[0])
   print(v1[0] is v3[0])
   print(v2[0] is v3[0])
   

   结果：

   True
   True
   True
   

8. 看代码写结果

   import copy
   
   v1 = [1,2,3,4,[11,22]]
   v2 = copy.copy(v1)
   v3 = copy.deepcopy(v1)
   
   print(v1[-1] is v2[-1])
   print(v1[-1] is v3[-1])
   print(v2[-1] is v3[-1])
   

   结果：

   True
   False
   False
   

9. 看代码写结果

   import copy
   
   v1 = [1,2,3,{"name":‘太白‘,"numbers":[7,77,88]},4,5]
   v2 = copy.copy(v1)
   
   print(v1 is v2)
   
   print(v1[0] is v2[0])
   print(v1[3] is v2[3])
   
   print(v1[3][‘name‘] is v2[3][‘name‘])
   print(v1[3][‘numbers‘] is v2[3][‘numbers‘])
   print(v1[3][‘numbers‘][1] is v2[3][‘numbers‘][1])
   

   结果：

   False
   True
   True
   True
   True
   True
   

10. 看代码写结果

    import copy
    
    v1 = [1,2,3,{"name":‘太白‘,"numbers":[7,77,88]},4,5]
    
    v2 = copy.deepcopy(v1)
    
    print(v1 is v2)
    
    print(v1[0] is v2[0])
    print(v1[3] is v2[3])
    
    print(v1[3][‘name‘] is v2[3][‘name‘])
    print(v1[3][‘numbers‘] is v2[3][‘numbers‘])
    print(v1[3][‘numbers‘][1] is v2[3][‘numbers‘][1])
    

    结果：

    False
    True
    False
    True
    False
    True
    
    

python深浅copy,is,id

原文：https://www.cnblogs.com/luxi526/p/12583723.html