Python - 键值相等的频率

给定一个字典，计算键等于值的实例。

Input : test_dict = {5:5, 8:9, 7:8, 1:2, 10:10, 4:8} 
Output : 2 
Explanation : At 2 instances, keys are equal to values.

Input : test_dict = {5:4, 8:9, 7:8, 1:2, 10:10, 4:8} 
Output : 1 
Explanation : At 1 instance, key is equal to value. 

方法#1：使用循环

在这种情况下，我们计算键等于值的实例并相应地增加计数器。

Python3

# Python3 code to demonstrate working of
# Keys Values equal frequency
# Using loop
  
# initializing dictionary
test_dict = {5: 5, 8: 9, 7: 7, 1: 2, 10: 10, 4: 8}
  
# printing original dictionary
print("The original dictionary is : " + str(test_dict))
  
res = 0
for key in test_dict:
  
    # checking for equality and incrementing counter
    if key == test_dict[key]:
        res += 1
  
# printing result
print("The required frequency : " + str(res))

输出

The original dictionary is : {5: 5, 8: 9, 7: 7, 1: 2, 10: 10, 4: 8}
The required frequency : 3

方法 #2：使用sum() +列表理解

其中，使用 sum() 执行计数任务，当找到相等的键值时，将 1 附加到列表中，然后在最后对每个值求和。

蟒蛇3

# Python3 code to demonstrate working of
# Keys Values equal frequency
# Using sum() + list comprehension
  
# initializing dictionary
test_dict = {5: 5, 8: 9, 7: 7, 1: 2, 10: 10, 4: 8}
  
# printing original dictionary
print("The original dictionary is : " + str(test_dict))
  
# computing summation to get frequency
res = sum([1 for key in test_dict if key == test_dict[key]])
  
# printing result
print("The required frequency : " + str(res))

输出

The original dictionary is : {5: 5, 8: 9, 7: 7, 1: 2, 10: 10, 4: 8}
The required frequency : 3