Python - Extract Keys with specific Value Type

Python – Extract Keys with specific Value Type

Last Updated : 11 Oct, 2020

Given a dictionary, extract all the keys, whose values are of given type.

Input : test_dict = {‘gfg’ : 2, ‘is’ : ‘hello’, ‘for’ : {‘1’ : 3}, ‘geeks’ : 4}, targ_type = int
Output : [‘gfg’, ‘geeks’]
Explanation : gfg and geeks have integer values.
Input : test_dict = {‘gfg’ : 2, ‘is’ : ‘hello’, ‘for’ : {‘1’ : 3}, ‘geeks’ : 4}, targ_type = str
Output : [‘is’]
Explanation : is has string value.

Method #1 : Using loop + isinstance()

In this, we check for data type using isinstance(), and iterate for all the values using loop.

Python3

# Python3 code to demonstrate working of
# Extract Keys with specific Value Type
# Using loop + isinstance()
  
# initializing dictionary
test_dict = {'gfg': 2, 'is': 'hello', 'best': 2, 'for': {'1': 3}, 'geeks': 4}
  
# printing original dictionary
print("The original dictionary is : " + str(test_dict))
  
# initializing type
targ_type = int
  
res = []
for key, val in test_dict.items():
  
    # checking for values datatype
    if isinstance(val, targ_type):
        res.append(key)
  
# printing result
print("The extracted keys : " + str(res))

Output:

The original dictionary is : {‘gfg’: 2, ‘is’: ‘hello’, ‘best’: 2, ‘for’: {‘1’: 3}, ‘geeks’: 4}
The extracted keys : [‘gfg’, ‘best’, ‘geeks’]

Method #2 : Using list comprehension + isinstance()

Similar to above method, one-liner shorthand to solve this problem using list comprehension.

Python3

# Python3 code to demonstrate working of
# Extract Keys with specific Value Type
# Using list comprehension + isinstance()
  
# initializing dictionary
test_dict = {'gfg': 2, 'is': 'hello', 'best': 2, 'for': {'1': 3}, 'geeks': 4}
  
# printing original dictionary
print("The original dictionary is : " + str(test_dict))
  
# initializing type
targ_type = int
  
# one-liner to solve the problem
res = [key for key, val in test_dict.items() if isinstance(val, targ_type)]
  
# printing result
print("The extracted keys : " + str(res))

Output:

The original dictionary is : {‘gfg’: 2, ‘is’: ‘hello’, ‘best’: 2, ‘for’: {‘1’: 3}, ‘geeks’: 4}
The extracted keys : [‘gfg’, ‘best’, ‘geeks’]

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