Python – Compare Dictionaries on certain Keys

Sometimes, while working with Python dictionaries, we can have a problem in which we need to compare dictionaries for equality on bases in selected keys. This kind of problem is common and has application in many domains. Lets discuss certain ways in which this task can be performed.

Method #1 : Using loop
This is brute force way in which this task can be performed. In this, we iterate for both the dictionary and manually test for keys equality using equality operator from selected keys.

# Python3 code to demonstrate working of
# Compare Dictionaries on certain Keys
# Using loop

# initializing dictionaries
test_dict1 = {'gfg' : 1, 'is' : 2, 'best' : 3, 'for' : 4, 'geeks' : 5}
test_dict2 = {'gfg' : 2, 'is' : 3, 'best' : 3, 'for' : 7, 'geeks' : 5}

# printing original dictionaries
print("The original dictionary 1 : " + str(test_dict1))
print("The original dictionary 2 : " + str(test_dict2))

# initializing compare keys
comp_keys = ['best', 'geeks']

# Compare Dictionaries on certain Keys
# Using loop
res = True
for key in comp_keys:
    if test_dict1.get(key) != test_dict2.get(key):
        res = False
        break

# printing result
print("Are dictionary equal : " + str(res))

Output :

The original dictionary 1 : {‘geeks’: 5, ‘gfg’: 1, ‘is’: 2, ‘for’: 4, ‘best’: 3}
The original dictionary 2 : {‘geeks’: 5, ‘gfg’: 2, ‘is’: 3, ‘for’: 7, ‘best’: 3}
Are dictionary equal : True

Method #2 : Using all()
This is one liner alternative to perform this task. In this the functionality of comparison is done using all(), comparing all required keys.

# Python3 code to demonstrate working of
# Compare Dictionaries on certain Keys
# Using all()

# initializing dictionaries
test_dict1 = {'gfg' : 1, 'is' : 2, 'best' : 3, 'for' : 4, 'geeks' : 5}
test_dict2 = {'gfg' : 2, 'is' : 3, 'best' : 3, 'for' : 7, 'geeks' : 5}

# printing original dictionaries
print("The original dictionary 1 : " + str(test_dict1))
print("The original dictionary 2 : " + str(test_dict2))

# initializing compare keys
comp_keys = ['best', 'geeks']

# Compare Dictionaries on certain Keys
# Using all()
res = all(test_dict1.get(key) == test_dict2.get(key) for key in comp_keys)

# printing result
print("Are dictionary equal : " + str(res))

Output :

The original dictionary 1 : {‘geeks’: 5, ‘gfg’: 1, ‘is’: 2, ‘for’: 4, ‘best’: 3}
The original dictionary 2 : {‘geeks’: 5, ‘gfg’: 2, ‘is’: 3, ‘for’: 7, ‘best’: 3}
Are dictionary equal : True