Build a dictionary from a list of keys and values in Python

This post will discuss how to build a dictionary from a list of keys and values in Python.

For example, keys = ['A', 'B', 'C'] and values = [1, 2, 3] should result in the dictionary {'A': 1, 'B': 2, 'C': 3}.

1. Using `zip()` with `dict()` function

The simplest and most elegant way to build a dictionary from a list of keys and values is to use the zip() function with a dictionary constructor.

if __name__ == '__main__':

keys = ['A', 'B', 'C']

values = [1, 2, 3]

dictionary = dict(zip(keys, values))

print(dictionary) # {'A': 1, 'B': 2, 'C': 3}

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2. Using Dictionary Comprehension

Another approach is to use the zip() with dictionary comprehension. This is often useful when you need value-key pairs instead of key-value pairs or apply some mapping function to each key or value. This can be implemented as:

if __name__ == '__main__':

keys = ['A', 'B', 'C']

values = [1, 2, 3]

dictionary = {k: v for k, v in zip(keys, values)}

print(dictionary) # {'A': 1, 'B': 2, 'C': 3}

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Here’s what the code would look like without zip():

if __name__ == '__main__':

keys = ['A', 'B', 'C']

values = [1, 2, 3]

dictionary = {keys[i]: values[i] for i in range(len(keys))}

print(dictionary) # {'A': 1, 'B': 2, 'C': 3}

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If you need to create a new dictionary with keys from iterable with the same value, you can do the following.

if __name__ == '__main__':

keys = ['A', 'B', 'C']

value = 1

dictionary = {key: value for key in keys}

print(dictionary) # {'A': 1, 'B': 1, 'C': 1}

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Alternatively, you can use the fromkeys() class function:

if __name__ == '__main__':

keys = ['A', 'B', 'C']

value = 1

dictionary = dict.fromkeys(keys, value)

print(dictionary) # {'A': 1, 'B': 1, 'C': 1}

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That’s all about building a dictionary from a list of keys and values in Python.

Build a dictionary from a list of keys and values in Python

1. Using zip() with dict() function

2. Using Dictionary Comprehension

1. Using `zip()` with `dict()` function