Python: extrae claves con un tipo de valor específico

Dado un diccionario, extrae todas las claves, cuyos valores son del tipo dado.

Entrada : test_dict = {‘gfg’: 2, ‘is’: ‘hola’, ‘for’: {‘1’: 3}, ‘geeks’: 4}, targ_type = int 
Salida : [‘gfg’, ‘geeks ‘] 
Explicación : gfg y geeks tienen valores enteros.

Entrada : test_dict = {‘gfg’: 2, ‘es’: ‘hola’, ‘para’: {‘1’: 3}, ‘geeks’: 4}, targ_type = str 
Salida : [‘es’] 
Explicación : tiene valor de string. 

Método #1: Usar loop + isinstance() 

En esto, verificamos el tipo de datos usando isinstance() e iteramos todos los valores usando loop.

# 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))

Producción:

El diccionario original es: {‘gfg’: 2, ‘is’: ‘hello’, ‘best’: 2, ‘for’: {‘1’: 3}, ‘geeks’: 4} Las claves extraídas: [‘ gfg’, ‘mejor’, ‘geeks’]

Método n.° 2: usar la comprensión de listas + isinstance()

Similar al método anterior, abreviatura de una sola línea para resolver este problema utilizando la comprensión de listas.

# 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))

Producción:

El diccionario original es: {‘gfg’: 2, ‘is’: ‘hello’, ‘best’: 2, ‘for’: {‘1’: 3}, ‘geeks’: 4} Las claves extraídas: [‘ gfg’, ‘mejor’, ‘geeks’]

Método #3: Usando los métodos keys() y type()

# Python3 code to demonstrate working of
# Extract Keys with specific Value Type
 
# 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 i in test_dict.keys():
    if type(test_dict[i]) is targ_type:
        res.append(i)
# printing result
print("The extracted keys : " + str(res))

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