How to Initialize a Dictionary With Keys in Python

This tutorial will discuss about unique ways to initialize a dictionary with keys in Python.

Table Of Contents

Using Dictionary comprehension

Suppose we have a list of keys and we want to create a dictionary from these keys.

But as the dictionary store the values in the key value pairs so, we want the value of each pair to be a default value 11.

We can do that using a dictionary comprehension. We will iterate over all the keys in the list using for loop. During iteration, for each key, we will create a key value pair and assign the default value 11 to that pair, and add it into the dictionary using the dictionary comprehension.

Let’s see the complete example,

listOfKeys = ['Ritika', 'Atharv', 'Smriti', 'Mathew', 'John']

# Default Value
value = 11

# Initialize a Dictionary using dictionary comprehension
dictObj = { key: value for key in listOfKeys }

print(dictObj)

Output

{'Ritika': 11, 'Atharv': 11, 'Smriti': 11, 'Mathew': 11, 'John': 11}

Using the fromkeys() method

Dictionary provides a method fromkeys(). It accepts two arguments, first is the list of keys and second is the value that every key should have in a new dictionary, and returns a new dictionary initialized withese arguments.

So, if you want to initialise a dictionary with the list, you can pass the list as the first argument and the default value as the second argument. It will return a dictionary object where each key will be picked from the list and every key will have the default value, which we provided as a second argument.

Like, the below example we are going to create a dictionary from the keys in the list and each key will have default value 11.

Let’s see the complete example,

listOfKeys = ['Ritika', 'Atharv', 'Smriti', 'Mathew', 'John']

# Default Value
value = 11

dictObj = dict.fromkeys(listOfKeys, value)

print(dictObj)

Output

{'Ritika': 11, 'Atharv': 11, 'Smriti': 11, 'Mathew': 11, 'John': 11}

Summary

We learned about two ways to Initialize a Dictionary With Keys in Python.