Merge Two Dictionaries in Python

By Atul Rai | Last Updated: January 22, 2025 Previous

To merge two dictionaries in Python, you can use several methods. Here are a few common ways:

1. Using the update() Method

The update() method updates the dictionary with elements from another dictionary object or from an iterable of key-value pairs.

# Using update() method
dict1 = {'a': 1, 'b': 2}
dict2 = {'b': 3, 'c': 4}

dict1.update(dict2)
print(dict1)  # Output: {'a': 1, 'b': 3, 'c': 4}

2. Using the ** Operator

The ** operator can be used to unpack dictionaries and merge them into a new dictionary.

# Using ** operator
dict1 = {'a': 1, 'b': 2}
dict2 = {'b': 3, 'c': 4}

merged_dict = {**dict1, **dict2}
print(merged_dict)  # Output: {'a': 1, 'b': 3, 'c': 4}

3. Using the | Operator (Python 3.9+)

Starting from Python 3.9, you can use the | operator to merge dictionaries.

# Using | operator (Python 3.9+)
dict1 = {'a': 1, 'b': 2}
dict2 = {'b': 3, 'c': 4}

merged_dict = dict1 | dict2
print(merged_dict)  # Output: {'a': 1, 'b': 3, 'c': 4}

4. Using Dictionary Comprehension

You can also use dictionary comprehension to merge dictionaries.

# Using dictionary comprehension
dict1 = {'a': 1, 'b': 2}
dict2 = {'b': 3, 'c': 4}

merged_dict = {k: v for d in (dict1, dict2) for k, v in d.items()}
print(merged_dict)  # Output: {'a': 1, 'b': 3, 'c': 4}

Note: Each of these methods will merge the dictionaries, with values from the second dictionary overwriting those from the first in case of key conflicts.

References

1. Python Dictionary with Examples