How do you Rename Keys in Python Dictionaries?

Renaming Dictionary Keys: A Comprehensive Solution

The Python dictionary is a versatile data structure that allows for efficient storage and retrieval of key-value pairs. However, certain scenarios may require the renaming of a key without altering its value or disturbing the dictionary's organization. This question addresses this issue and provides a range of solutions tailored to both regular dictionaries and OrderedDicts.

Regular Dict

For a regular dictionary, a simple approach involves using the pop() method to remove the old key and the [] operator to assign the value to the new key:

<code class="python">mydict["k_new"] = mydict.pop("k_old")</code>

This operation effectively moves the item to the end of the dictionary unless k_new already exists, in which case it overwrites the value in place.

OrderedDict

OrderedDict, introduced in Python 3.7, preserves the insertion order of key-value pairs. To rename a key while maintaining order:

<code class="python">OrderedDict((k_new if k == k_old else k, v) for k, v in od.items())</code>

This reassigns values to new keys using a generator expression, ensuring the order is retained.

Preserving Ordering in Python 3.7 Dict

Python 3.7 dictionaries natively uphold insertion order. To rename a key while preserving this order:

<code class="python">d = {0:0, 1:1, 2:2, 3:3}
{k: v for k, v in d.items() if k != k_old} | {k_new: d[k_old]}</code>

Modifying the Key Itself

The question asks about modifying the key itself. However, since keys are hashable and immutable in Python, direct key modification is not feasible. However, by reassigning the value with the desired key name and removing the old key, the dictionary remains intact, effectively "renaming" the key without directly modifying it.

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