Removing dictionary entries in Python - Cheat Sheet & Quick Revision

Recall & Review

beginner

How do you remove a key-value pair from a dictionary using the del statement?

Use del dict[key] to remove the entry with the specified key from the dictionary.

beginner

What does the pop() method do in a dictionary?

The pop(key) method removes the key-value pair with the given key and returns its value. If the key is not found, it raises a KeyError unless a default value is provided.

intermediate

How can you safely remove a key from a dictionary without causing an error if the key does not exist?

Use pop(key, default_value) where default_value is returned if the key is missing, preventing an error.

intermediate

What is the difference between popitem() and pop() in dictionaries?

popitem() removes and returns the last inserted key-value pair as a tuple, while pop(key) removes the pair with the specified key.

advanced

Can you remove multiple entries from a dictionary at once? If yes, how?

Yes, by using a loop to remove keys one by one or by creating a new dictionary excluding unwanted keys.

Which statement removes the key 'age' from the dictionary person?

A del person['age']

B person.remove('age')

C person.popitem('age')

D person.delete('age')

The del statement with the key removes that entry from the dictionary.

What does person.pop('name') return?

A The value associated with 'name' and removes it from the dictionary

B Removes 'name' but returns None

C Removes the last item in the dictionary

D Raises an error if 'name' exists

pop(key) returns the value for the key and removes the key-value pair.

How can you avoid an error when removing a key that might not exist?

A Use <code>popitem()</code>

B Use <code>del dict[key]</code> without checking

C Use <code>remove(key)</code>

D Use <code>pop(key, default)</code>

Providing a default value to pop() prevents errors if the key is missing.

What does popitem() do?

A Removes all items

B Removes a specified key

C Removes and returns the last inserted key-value pair

D Returns the value of a key without removing it

popitem() removes and returns the last inserted pair as a tuple.

Which method is NOT used to remove entries from a dictionary?

A pop()

B remove()

C del

D popitem()

remove() is not a dictionary method; it is used with lists.

Explain three ways to remove entries from a Python dictionary and when to use each.

Think about whether you want the removed value or just to delete.

How can you safely remove a key from a dictionary without causing an error if the key does not exist?

Consider methods that provide a fallback value.