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Dictionary is a data type that represents a collection of objects indexed by a "key" rather than by a numerical index
(like 0, 1, 2).
Syntax of dictionary is as follows:

dictionary_name = { key1: value1, key2: value2, key3: value3}
Note: Instead of using numbers to find items (like in a list), you use a "Key" (a label) to find a "Value" (the
information).

Program 13: To display the output of following code using mapping.
Program 13.py

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# Creating a dictionary of student details
student = {
"name": "Rahul",
"age": 15,
"grade": "A"
}
# Printing the complete dictionary
print(student)
# Accessing value using key "name"
print("Name of student:", student["name"])
# Accessing value using key "age"
print("Age of student:", student["age"])

Output

{'name': 'Rahul', 'age': 15, 'grade': 'A'}
Name of student: Rahul
Age of student: 15

12.6.1 Characteristics of Dictionary data types in Python
There are some characteristics of Dictionary data types in Python:
• Key–Value Pair Structure: A dictionary stores data in the form of key–value pairs. Each key is associated with a
specific value.
• Unordered Collection (Insertion Ordered in Modern Python): Dictionaries maintain insertion order (from Python
3.7 onward), but elements are accessed using keys, not index numbers.
• Mutable: Dictionaries are changeable. You can add, update or remove key–value pairs after creation.
• Unique Keys: Each key in a dictionary must be unique. Duplicate keys are not allowed.

• Values Can Be Duplicated: While keys must be unique, values can be repeated.
• Accessed by Keys: Elements are accessed using their keys instead of index positions.
• Can Store Different Data Types: Keys and values can be of different data types (e.g., string, integer, float, etc.).
• Dynamic Size: The size of a dictionary can grow or shrink as elements are added or removed.

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