Python – Keys Values equal frequency

Given a dictionary, count instances where keys are equal to values.

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. 

Method #1 : Using loop

In this, we count instances where keys are equal to values and increment the counter accordingly.

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))

Output

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

Method #2 : Using sum() + list comprehension

In this, task of counting is performed using sum(), when equal key-values are found, 1 is appending to list, and then at end, each value is summed.

Python3

# 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))

Output

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