How to Remove Elements from a Python Dictionary: Del or Shallow Copy?

Delete an Element from a Dictionary

When working with dictionaries in Python, there may come a time when you need to remove an element. This can be achieved in two ways:

1. Modifying the Original Dictionary

Using the del statement, you can directly remove an element from the dictionary, thereby modifying the original dictionary:

<code class="python">del d[key]</code>

where d is the dictionary and key is the key of the element to be removed.

2. Obtain a New Dictionary without the Element

To obtain a new dictionary with the element removed, without modifying the original dictionary, you can use the following method:

<code class="python">def removekey(d, key):
    r = dict(d)
    del r[key]
    return r</code>

This function first creates a copy of the original dictionary d using the dict() constructor. Then, it removes the specified key from the copy and returns the modified copy r as a new dictionary.

Note:

• The dict() constructor performs a shallow copy, meaning that changes made to the new dictionary will not affect the original dictionary and vice versa.
• For large dictionaries, creating copies for every deletion operation can be inefficient. Consider using a different data structure, such as a HAMT (hashed array-mapped trie), for efficient element removal.

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