Python – 字典中自定义嵌套键的总和

给定带有键作为嵌套字典的字典，找到嵌套字典中某些自定义键的值的总和。

Input : test_dict = {‘Gfg’ : {1 : 6, 5: 9, 9: 12}, ‘is’ : {1 : 9, 5: 7, 9: 2}, ‘best’ : {1 : 3, 5: 4, 9: 14}}, sum_key = [1]
Output : 18
Explanation : 6 + 9 + 3 = 18, only values with key 1 are summed.

Input : test_dict = {‘Gfg’ : {1 : 6, 5: 9, 9: 12}, ‘is’ : {1 : 9, 5: 7, 9: 2}, ‘best’ : {1 : 3, 5: 4, 9: 14}}, sum_key = [5, 9]
Output : 48
Explanation : Keys 5, 9 are summed.

方法#1：循环

这是可以解决此问题的粗暴方式。在此，我们对所有列表元素使用循环，并不断更新所有嵌套字典的总和值。

Python3

# Python3 code to demonstrate working of 
# Summation of Custom nested keys in Dictionary
# Using loop
  
# initializing dictionary
test_dict = {'Gfg' : {1 : 6, 5: 9, 9: 12},
             'is' : {1 : 9, 5: 7, 9: 2}, 
             'best' : {1 : 3, 5: 4, 9: 14}}
  
# printing original dictionary
print("The original dictionary is : " + str(test_dict))
  
# initializing sum keys 
sum_key = [1, 9]
  
sum = 0
for ele in sum_key:
    for key, val in test_dict.items():
          
        # extracting summation of required values
        sum = sum + val[ele]
  
# printing result 
print("The required summation : " + str(sum))

输出

The original dictionary is : {‘Gfg’: {1: 6, 5: 9, 9: 12}, ‘is’: {1: 9, 5: 7, 9: 2}, ‘best’: {1: 3, 5: 4, 9: 14}}
The required summation : 46

方法 #2：使用列表理解 + sum()

上述功能的组合也可以用来解决这个问题。在此，我们使用 sum() 执行求和任务，其余逻辑也使用列表理解封装为单行。

Python3

# Python3 code to demonstrate working of 
# Summation of Custom nested keys in Dictionary
# Using list comprehension + sum()
  
# initializing dictionary
test_dict = {'Gfg' : {1 : 6, 5: 9, 9: 12},
             'is' : {1 : 9, 5: 7, 9: 2}, 
             'best' : {1 : 3, 5: 4, 9: 14}}
  
# printing original dictionary
print("The original dictionary is : " + str(test_dict))
  
# initializing sum keys 
sum_key = [1, 9]
  
# sum() used to get cumulative summation
res = sum([val[ele] for ele in sum_key for key, val in test_dict.items()])
  
# printing result 
print("The required summation : " + str(res)) 

输出

The original dictionary is : {‘Gfg’: {1: 6, 5: 9, 9: 12}, ‘is’: {1: 9, 5: 7, 9: 2}, ‘best’: {1: 3, 5: 4, 9: 14}}
The required summation : 46