Dictionary iteration in Python - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is dictionary iteration in Python?

Dictionary iteration means going through each key or value in a dictionary one by one to use or check them.

beginner

How do you iterate over keys in a Python dictionary?

Use a for loop directly on the dictionary, like for key in my_dict:. This loops over all keys.

beginner

How can you get both keys and values when iterating a dictionary?

Use for key, value in my_dict.items(): to get each key and its value together.

beginner

What does my_dict.values() do in dictionary iteration?

It gives you all the values in the dictionary, so you can loop over just the values without keys.

beginner

Why is dictionary iteration useful in programming?

It helps you check, change, or use each piece of data stored in the dictionary easily, like looking up phone numbers or settings.

Which method lets you loop over both keys and values in a dictionary?

A items()

B keys()

C values()

D all()

The items() method returns key-value pairs for iteration.

What does this code print?
my_dict = {'a':1, 'b':2}
for key in my_dict:
print(key)

A 1 and 2

B Nothing

C 'a' and 'b'

D Error

Looping over a dictionary directly gives its keys.

How do you loop over only the values in a dictionary?

A for val in my_dict.keys():

B for val in my_dict.values():

C for val in my_dict.items():

D for val in my_dict:

The values() method returns all values for iteration.

What type of object does my_dict.items() return?

A String

B List of values

C List of keys

D View of key-value pairs

items() returns a view object showing key-value pairs.

Which of these is NOT a way to iterate a dictionary?

A for i in range(my_dict):

B for key in my_dict:

C for val in my_dict.values():

D for key, val in my_dict.items():

You cannot use range() directly on a dictionary.

Explain how to loop through a dictionary to get both keys and values.

Think about the method that returns pairs.

Why might you want to iterate over just the keys or just the values in a dictionary?

Consider what you need from the dictionary.