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Hello Pythonistas, welcome back. This Python Merging Dictionaries guide includes various ways to merge dictionaries in Python quickly.

python merging dictionaries python merging dictionaries

Can you combine dictionaries in Python?

Yes, you can combine 2 or more dictionaries.

There are various methods for this—much more than the ones mentioned here.

These are the most used ones.

Python Merging Dictionaries: With a Basic Approach

The simplest way anyone would think of is adding values to the first dictionary using a for loop.

The steps are simple:

1. Create the two dictionaries
2. Create a deep copy of the first dictionary.
3. Loop through the second dictionary.
   • On every iteration store the key-value pair into the copied dictionary.

And you are done.

dict1 = {"a": 1, "b": 2}
dict2 = {"c": 3, "d": 4}

merged_dict = dict1.copy()

for key, value in dict2.items():
    merged_dict[key] = value

print(merged_dict)

#OUTPUT:
# {'a': 1, 'b': 2, 'c': 3, 'd': 4}

How do I merge two dictionaries in Python using update?

Now if you don’t want to work that hard you can opt the other way.

Using the update() method.

Here are the steps:

1. Create the two dictionaries.
2. Call the update() method on the first dictionary and pass the second dictionary as an argument.
3. Remember this updates the original dictionary.

dict1 = {"a": 1, "b": 2}
dict2 = {"c": 3, "d": 4}

dict1.update(dict2)
print(dict1)

#OUTPUT:
# {'a': 1, 'b': 2, 'c': 3, 'd': 4}

How do I merge two nested dictionaries in Python?

This can be done just as before using the update() method.

Steps are:

1. Create 2 nested dictionaries
2. Call the update() method on the first dictionary and pass the second dictionary as an argument.
3. Remember this updates the original dictionary.

dict1 = {"John": {'Age':10, 'Marks':93}, "Jane": {'Age':15, 'Marks':89}}
dict2 = {"Jenny": {'Age':9, 'Marks':73}, "Jimmy": {'Age':20, 'Marks':100}}

dict1.update(dict2)
print(dict1)

#OUTPUT:
# {'John': {'Age': 10, 'Marks': 93}, 'Jane': {'Age': 15, 'Marks': 89}, 'Jenny': {'Age': 9, 'Marks': 73}, 'Jimmy': {'Age': 20, 'Marks': 100}}

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