Can You Delete Items from a Python Dictionary During Iteration?

Can You Remove Items from a Dictionary during Iteration?

When manipulating dictionaries in Python, the question of deleting items while iterating over the keys arises. Here's how to achieve this effectively.

Option for Python 3

In Python 3, you can iterate over a list of keys obtained from the keys() method:

<code class="python">for k in list(mydict.keys()):
    if mydict[k] == 3:
        del mydict[k]</code>

Option for Python 2

In Python 2, the iterkeys() method returns an iterator instead of a list. Therefore, modifying the dictionary while iterating over iterkeys() raises a RuntimeError. Instead, use the keys() method to get a list of keys:

<code class="python">for k in mydict.keys():
    if k == 'two':
        del mydict[k]</code>

For deleting based on item values, iterate over the items() method:

<code class="python">for k, v in mydict.items():
    if v == 3:
        del mydict[k]</code>

Remember to be cautious when modifying dictionaries during iteration, as it can disrupt the iteration process.

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