CRUD Operations on a Dictionary

Create

A dictionary is created with key-value pairs.
Keys include name, age, class, and subjects.

student = {'name': 'Tom', 'age': 17, 'class': '24/12', 'subjects': ['math', 'computing', 'physics', 'economics']}
print(student)

--------------------------------------- {'name': 'Tom', 'age': 17, 'class': '24/12', 'subjects': ['math', 'computing', 'physics', 'economics']}

Read

Access dictionary values using get() or direct indexing.
get() is safer as it does not throw an error for missing keys.

print(student.get('age'))  # Output: 17
print(student.get('id'))   # Output: None

---------------------------------------

17
None

Update

Update values of keys or modify nested elements (e.g., a list inside the dictionary).

student['class'] = '24/13'  # Update class
student['subjects'][1] = 'biology'  # Update subject
print(student)

--------------------------------------- {'name': 'Tom', 'age': 17, 'class': '24/13', 'subjects': ['math', 'biology', 'physics', 'economics']}

Delete

Use del or pop() to remove key-value pairs.

del student['age']
student.pop('subjects')
print(student)

--------------------------------------- {'name': 'Tom', 'class': '24/13'}

Insert

Add new key-value pairs to the dictionary.

student['teacher'] = 'Mr Tan'
print(student)

--------------------------------------- {'name': 'Tom', 'class': '24/13', 'teacher': 'Mr Tan'}

Dictionary Operations Summary

Keys: Use student.keys() to display all keys.
Values: Use student.values() to display all values.
Items: Use student.items() to get key-value pairs.
Length: Use len() to get the size of the dictionary.

print(student.keys())
print(student.values())
print(student.items())
print(len(student))