9.12. Dictionary in Python

A dictionary in Python stores data in key-value pairs.

A dictionary is a built-in data structure in Python that allows you to store data in pairs called key-value pairs. Each key is unique, and it serves as an identifier for the corresponding value, which can be of any data type. By using this structure, you can easily retrieve, add, or modify elements based on their keys.

Think of a dictionary like a real-world dictionary where you look up a word (key) to find its definition (value). Each word is unique, just like each key in a Python dictionary.

Example of a dictionary:

student = {
"name": "Amit",
"age": 17,
"grade": "11th"
}

In this example, we create a dictionary named 'student' which contains three key-value pairs. The key 'name' is associated with the value 'Amit', the key 'age' with the value 17, and 'grade' with '11th'. Each pair is separated by commas, and the entire dictionary is defined within curly braces {}.

Consider the dictionary as a student profile where you have 'name', 'age', and 'grade' as labels (keys) pointing to specific information about the student. For instance, you can think of it like a student ID card that has specific fields detailing the student's identity.

You can access the value of a key using the following syntax:

print(student["name"])

To retrieve a value from a dictionary, you use the key enclosed in square brackets. For example, student["name"] will return the value associated with the key 'name', which in this case is 'Amit'. This method of accessing values is quick and efficient because dictionaries are optimized for this kind of lookup.

Imagine you are accessing information from a filing cabinet: if you know the label on the folder (the key), you can quickly pull out the information you need (the value) without searching through every paper.

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