Python – Create a dictionary using list with none values

Sometimes you might need to convert a list to dict object for some better and fast operation. Let’s see how to convert a list into a dictionary of none values. Here we will find three methods of doing this.

Method #1: Using zip()and dict 

Python3

# Python code to demonstrate
# converting list into dictionary with none values
# using zip() and dictionary

# initializing list
ini_list = [1, 2, 3, 4, 5]

# printing initialized list
print ("initial list", str(ini_list))

# Converting list into dictionary using zip() and dictionary
res = dict(zip(ini_list, [None]*len(ini_list)))

# printing final result
print ("final dictionary", str(res))

Output:

initial list [1, 2, 3, 4, 5]
final dictionary {1: None, 2: None, 3: None, 4: None, 5: None}

Method #2: Using dict 

Python3

# Python code to demonstrate converting
# list into dictionary with none values
# using dict()

# initializing list
ini_list = [1, 2, 3, 4, 5]

# printing initialized list
print ("initial list", str(ini_list))

# Converting list into dict()
res = dict.fromkeys(ini_list)

# printing final result
print ("final dictionary", str(res))

Output:

initial list [1, 2, 3, 4, 5]
final dictionary {1: None, 2: None, 3: None, 4: None, 5: None}

Method #3: Using dict comprehension

Python3

# Python code to demonstrate converting
# list into dictionary with none values
# using dict comprehension

# initializing list
ini_list = [1, 2, 3, 4, 5]

# printing initialized list
print ("initial list", str(ini_list))

# Converting list into dict()
res = {key: None for key in ini_list}

# printing final result
print ("final dictionary", str(res))

Output:

initial list [1, 2, 3, 4, 5]
final dictionary {1: None, 2: None, 3: None, 4: None, 5: None}