NCERT Class 11 Computer Science Computer Science: Chapter 9 — Lists
This chapter introduces the concept of Lists in Python, a fundamental data structure. It defines a list as an ordered, mutable sequence that can contain elements of various data types, enclosed in square brackets and separated by commas. The chapter explains how list indices start from 0, similar to strings, and demonstrates accessing elements using positive and negative indices. It highlights the mutability of lists, allowing their contents to be modified after creation. The text also introduces list operations, starting with concatenation using the '+' operator to combine lists. This chapter is crucial for Class 11 Computer Science students to understand data organization and manipulation in Python programming.
Quick info
| Board | CBSE / NCERT |
|---|---|
| Class | Class 11 |
| Subject | Computer Science |
| Book | Computer Science |
| Chapter | Chapter 9 — Lists |
| Language | English |
| PDF type | NCERT Textbook |
| Session | CBSE 2026 |
| Reading time | 3 minutes |
| Word count | 457 |
Learning outcomes
- Understand the definition and characteristics of a Python list.
- Differentiate lists from strings and other data types.
- Access list elements using positive and negative indexing.
- Recognize and demonstrate the mutability of lists.
- Perform list concatenation to combine multiple lists.
Vocabulary
| Word | Meaning |
|---|---|
| List | An ordered, mutable sequence of elements, enclosed in square brackets. |
| Mutable | Capable of being changed or altered after creation. |
| Ordered sequence | Elements are arranged in a specific order and can be accessed by their position. |
| Elements | Individual items within a list. |
| Data types | Categories of data, such as integer, float, string, etc. |
| Indices | The position of an element in a list, starting from 0. |
| Concatenation | The operation of joining two or more lists together. |
| Nested list | A list that contains other lists as its elements. |
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Practice questions
- What is a list in Python? Answer: A list is an ordered, mutable sequence that can contain elements of different data types.
- How are elements in a list accessed? Answer: Elements are accessed using indices, starting from 0 for the first element.
- What does it mean for a list to be mutable? Answer: It means the contents of the list can be changed after it has been created.
- What operator is used for list concatenation? Answer: The '+' operator is used for list concatenation.
Frequently asked questions
What is the primary characteristic of a Python list?
A Python list is an ordered, mutable sequence that can hold elements of various data types.
Can a list contain elements of different data types?
Yes, unlike strings, lists can contain elements of mixed data types like integers, floats, strings, and even other lists.
How do you access elements in a list?
Elements are accessed using their index, which starts from 0 for the first element. Negative indices can be used to access elements from the end.
What does 'mutable' mean in the context of lists?
Mutable means that the elements within a list can be changed, added, or removed after the list has been created.
How can you combine two lists in Python?
You can combine two lists using the concatenation operator '+', which joins the elements of the second list to the end of the first.
What is a nested list?
A nested list is a list that contains other lists as its elements.
Related resources
Important topics
Topics covered
NCERT Class 11 Computer Science — Computer Science — Chapter 9 — Lists. Verified by NCERT Help Editorial Team. Reviewed on 29 Jul 2026. Last updated 10 Aug 2026.