Changing Key Names in Python Dictionaries
Renaming keys in a dictionary is a common task in Python programming. This guide explains how to efficiently update key names using two different methods.
Method 1: Two-Step Approach
Assign the value associated with the old key to a new key:
dictionary[new_key] = dictionary[old_key]
Delete the old key from the dictionary:
del dictionary[old_key]
Method 2: One-Step Approach
Combine both steps into a single line using the pop() method:
dictionary[new_key] = dictionary.pop(old_key)
This approach is useful when you don't need to access the old value after changing the key. However, it's important to note that it will raise a KeyError exception if the old key doesn't exist.
Example
Consider the following dictionary:
dictionary = { 1: 'one', 2: 'two', 3: 'three' }
To change the key of 'one' from 1 to 'ONE':
dictionary['ONE'] = dictionary.pop(1)
The resulting dictionary will be:
dictionary = { 2: 'two', 3: 'three', 'ONE': 'one' }
By following these methods, you can easily modify key names in Python dictionaries, maintaining the integrity and consistency of your data.
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