How to Create a Dictionary from List in Python?

This tutorial will discuss about unique ways to create a dictionary from list in Python.

Table Of Contents

Using Dictionary Comprehension

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

We can iterate over the string in list, inside the dictionary comprehension. For each string we will make it as the key in a key-value pair, and the value in that pair will be the length of that string key.

All this will be done in a single line usng Dictionary Comprehension.

Let’s see the complete example,

listOfKeys = ['John', 'Avisha', 'Varun', 'Riti']

# Create a Dictionary from a List
dictObj = {item: len(item) for item in listOfKeys}

print(dictObj)

Output

{'John': 4, 'Avisha': 6, 'Varun': 5, 'Riti': 4}

Using a For-Loop

Now if you don’t want to use the dictionary comprehension, then we can do the same thing using a simple for loop.

Iterate about all the strngs in the list and for each string in the list, add it as a key in the dictionary and assign the value as a length of this string item.

the value field will be the number of characters in this string key. So when the for loop end, we will have a dictionary, where each item of the dictionary will have a key from the list and its value will be the number of characters in the key string.

Let’s see the complete example,

listOfKeys = ['John', 'Avisha', 'Varun', 'Riti']

dictObj = {}
for item in listOfKeys:
    dictObj[item] = len(item)

print(dictObj)

Output

{'John': 4, 'Avisha': 6, 'Varun': 5, 'Riti': 4}

Summary

We learned about two different wasy to create a Dictionary from a List in python.