PYTHON — Merging And Updating Dictionaries With Operators In Python

The most dangerous phrase in the language is, ‘We’ve always done it this way.’ — Grace Hopper

Insights in this article were refined using prompt engineering methods.

PYTHON — Understanding Python Questions

Merging and updating dictionaries with operators in Python can be achieved using the new merge (|) and update (|=) dictionary operators introduced in Python 3.9. These operators also work with OrderedDict instances. The merge operator combines the items of two dictionaries into a new one, with the rightmost dictionary's value being used for any common keys. On the other hand, the update operator is useful for updating a dictionary's values without having to call .update().

Here’s an example of using the merge 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}

In the above example, the value of 'b' from dict2 prevailed over the value from dict1. The resulting merged_dict contains the merged key-value pairs.

The update operator is used to update a dictionary in place, as shown in the following example:

dict3 = {'name': 'Isaac Newton', 'occupation': 'scientist'}
update_data = {'name': 'Sir Isaac Newton', 'lifetime': '1643-1727'}
dict3 |= update_data
print(dict3)

Output:

{'name': 'Sir Isaac Newton', 'occupation': 'scientist', 'lifetime': '1643-1727'}

In this case, the dictionary dict3 was updated with the new values from update_data, and the new key 'lifetime' was added to the end of the original dictionary.

It is important to note that the update operator modifies the dictionary in place, while the merge operator returns a new dictionary without modifying the original ones.

These operators provide a convenient and concise way to merge and update dictionaries in Python.

PYTHON — How To Format Your List Comprehensions In Python