Safe access using get() in Python - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the get() method do in a Python dictionary?

It safely retrieves the value for a given key. If the key is not found, it returns None or a specified default value instead of raising an error.

beginner

How do you provide a default value when using get()?

You pass the default value as the second argument to get(). For example, my_dict.get('key', 'default') returns 'default' if 'key' is missing.

beginner

Why is using get() safer than directly accessing a dictionary key?

Direct access like my_dict['key'] raises a KeyError if the key is missing. get() avoids this by returning None or a default value, preventing program crashes.

beginner

What will my_dict.get('age', 30) return if 'age' is not in my_dict?

It will return 30, the default value provided.

intermediate

Can get() be used with nested dictionaries to avoid errors?

Yes, but only for one level at a time. For nested dictionaries, you can chain get() calls or use other methods to safely access deeper keys.

What does my_dict.get('key') return if 'key' is not present?

A Zero

B Raises KeyError

C Empty string

D None

get() returns None by default if the key is missing.

How do you specify a default value of 100 when using get()?

A my_dict.get(100, 'key')

B my_dict.get('key', 100)

C my_dict['key'].get(100)

D my_dict.get('key').default(100)

The second argument to get() is the default value returned if the key is missing.

Which of these will cause a program crash if the key is missing?

A my_dict['missing_key']

B None of the above

C my_dict.get('missing_key', 'default')

D my_dict.get('missing_key')

Direct access with square brackets raises KeyError if the key is missing.

What type of object is get() called on?

A List

B String

C Dictionary

D Integer

get() is a method of Python dictionaries.

If my_dict = {'a': {'b': 2}}, what does my_dict.get('a').get('b') return?

A 2

B None

C Raises KeyError

D Raises AttributeError

First get('a') returns the nested dict, then get('b') returns 2.

Explain how the get() method helps avoid errors when accessing dictionary keys.

Think about what happens if the key is missing.

Describe how to use get() with a default value and why it is useful.

What do you pass to <code>get()</code> besides the key?