Day 17: Dictionary Basics

Quick Answer

What You Will Learn

• marks = {"Arhan": 92} creates a dict inside curly brackets, in key: value pairs.
• marks["Arhan"] returns 92 by looking up the key.
• marks.get("Aman", 0) returns 0 when the key is missing, instead of raising KeyError.
• update() adds a new key or changes the value of an existing key.
• .items() gives key and value together in a loop; list(marks) gives only the keys.

Code

marks = {"Arhan": 92, "Riya": 85}
print(marks["Arhan"])
print(marks.get("Aman", 0))
marks.update({"Riya": 88})
print(marks)
for name, m in marks.items():
    print(name, m)
print(list(marks))

Output

92
0
{'Arhan': 92, 'Riya': 88}
Arhan 92
Riya 88
['Arhan', 'Riya']

Code Explained, Line by Line

1. marks = {"Arhan": 92} creates a dict inside curly brackets, in key: value pairs.
2. marks["Arhan"] returns 92 by looking up the key.
3. marks.get("Aman", 0) returns 0 when the key is missing, instead of raising KeyError.
4. update() adds a new key or changes the value of an existing key.
5. .items() gives key and value together in a loop; list(marks) gives only the keys.

Real-Life Use

Phonebooks, user profiles and JSON data from APIs are all dictionaries.

Test Yourself — MCQs

Select (tick) an option, then tap Check answer to see instantly whether your answer is right or wrong, with an explanation. You can change your answer and check again.

Today's 5 Reels (from the 90-Day Plan Excel)