CBSE Class 11 Computer Science Chapter 13: Lists, Dictionaries and Tuples NCERT Solutions

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NCERT Solutions PDF Class 11 PDF

This chapter delves into fundamental Python data structures, focusing on Lists, Dictionaries, and Tuples. The NCERT Solutions provide clear explanations and answers to questions related to sequence types, list manipulation, and built-in functions. Students will learn about creating, accessing, and modifying lists, understanding slicing, and utilizing methods like append, extend, count, and remove. The solutions also cover functions for comparing lists, finding minimum and maximum elements, and converting between data types. This resource is designed to help Class 11 Computer Science students grasp these essential programming concepts, reinforcing their understanding through practice questions and detailed answers, crucial for exam preparation.

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Quick info

BoardCBSE
ClassClass 11
SubjectComputer Science
Session2026
LanguageEnglish
TypeNCERT Solutions
ChapterChapter 13

Chapter summary

This chapter's NCERT Solutions cover Python's built-in sequence types, with a primary focus on lists. It addresses various aspects of list manipulation, including accessing elements, slicing, removing elements using 'del' and 'remove()', and comparing lists. Key list methods such as append(), extend(), count(), len(), max(), and min() are explained. The solutions also touch upon converting sequences like tuples to lists. This section is vital for building a strong foundation in Python programming for Class 11 students.

Learning outcomes

  • Identify the different types of built-in sequence types in Python.
  • Understand and apply list indexing and slicing to access elements.
  • Learn methods for removing elements from a list.
  • Explain the functionality of list methods like append(), extend(), and count().
  • Describe the purpose of built-in functions like len(), max(), and min() for lists.
  • Understand how to compare lists and convert sequences to lists.

Topics covered

Paper topics

  • Python Sequence Types
  • Lists in Python
  • List Indexing
  • List Slicing
  • Removing List Elements
  • List Comparison
  • Built-in List Functions (len, max, min)
  • List Methods (append, extend, count)
  • Tuple to List Conversion

Important topics

  • Understanding Python Lists
  • List Indexing and Slicing
  • List Manipulation Methods (append, extend, remove)
  • Built-in Functions for Lists (len, max, min)
  • Sequence Types in Python

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Questions and Solutions

Question 1

How many types of built-in types of sequences are there in Python?
Solution:

Python offers a total of six distinct built-in types of sequences. These sequence types are fundamental data structures used for storing collections of items in an ordered manner.

Question 2

Write the output of the given Python code:

#!/user/bin/python

list1 = ['physics', 'chemistry', 1997, 2000];

list2 = [1,2,3,4,5,6,7];

print "list1[0]", list1[0]

Solution:

The code initializes two lists, list1 and list2. It then prints the element at index 0 of list1. List indices in Python start from 0.

Output:

list1[0]: physics

Question 3

Write the output of the given Python code:

#!/user/bin/python

listl = ['physics', 'chemistry', 1997,2000];

list2 = [1,2,3,4,5,6,7];

print "list2[1:5[", list2[1:5]

Solution:

This Python code snippet initializes two lists, list1 and list2. It then proceeds to print a slice of list2. The slice list2[1:5] extracts elements starting from index 1 up to (but not including) index 5. Remember that Python list indices are 0-based.

Output:

list2[1:5[: [2,3,4,5]

Question 4

How can we remove a list element in Python?
Solution:

To remove an element from a list in Python, you have a couple of primary options:

  • Using the del statement: This statement removes an element at a specific index. For example, del list_name[index].
  • Using the remove() method: This method removes the first occurrence of a specified value from the list. For example, list_name.remove(value).

Question 5

Why do we use the cmp(list1, list2) function in Python?
Solution:

The cmp(list1, list2) function is used to compare the elements of two lists lexicographically. It returns -1 if list1 is less than list2, 0 if they are equal, and 1 if list1 is greater than list2. Note: This function has been removed in Python 3 and replaced by comparison operators.

Question 6

What is the use of len(list) in Python?
Solution:

The built-in function len(list) is used to determine and return the total number of elements present in the list. It provides the length or size of the list.

Question 7

Describe the max(list) method.
Solution:

The max(list) function is a built-in Python function that iterates through the list and returns the item from the list that has the maximum value. This function requires that the elements in the list are comparable (e.g., all numbers or all strings).

Question 8

Describe the min(list) method.
Solution:

The min(list) function is a built-in Python function that iterates through the list and returns the item from the list that has the minimum value. Similar to max(), this function requires that the elements in the list can be compared with each other.

Question 9

What is the use of list(seq) in Python?
Solution:

The list(seq) constructor is used to convert a sequence (such as a tuple, string, or another iterable) into a list. For example, if you have a tuple, list(my_tuple) will create a new list containing the same elements in the same order.

Question 10

What do you mean by list.append(obj)?
Solution:

The list.append(obj) method is used to add an object (obj) to the very end of the list. It modifies the original list in place by increasing its length by one.

Question 11

What do you mean by list.count(obj)?
Solution:

The list.count(obj) method returns the number of times a specified object (obj) appears within the list. It counts all occurrences of the object.

Question 12

Explain list.extend(seq).
Solution:

The list.extend(seq) method is used to append all the items from an iterable sequence (seq), such as another list or a tuple, to the end of the current list. It effectively concatenates the contents of seq onto the existing list.

Common mistakes

  • Incorrectly using list slicing indices, leading to unexpected results.
  • Confusing the 'remove()' method with 'del' statement for element removal.
  • Misunderstanding the difference between appending a single element and extending with a sequence.
  • Errors in accessing elements due to off-by-one errors in indexing.

Revision tips

  • Practice creating lists with various data types and practice accessing elements using both positive and negative indices.
  • Experiment with different slicing techniques to understand how to extract sub-lists.
  • Write small Python programs to test each list method (append, extend, count, remove) to see its effect.
  • Review the purpose of built-in functions like len(), max(), and min() and apply them to different list scenarios.

Practice MCQs

Q1. How many built-in types of sequences are available in Python?

Q2. Which method is used to add an object to the end of a list?

Q3. What does the list.count(obj) method return?

Q4. Which function returns the item from the list with the maximum value?

Q5. What is the primary use of the list.extend(seq) method?

Frequently asked questions

What are the main sequence types in Python covered in this chapter?

This chapter focuses on Python's built-in sequence types, primarily lists, and also touches upon tuples in the context of conversion to lists.

How can I remove an element from a list in Python?

You can remove a list element using the 'del' statement or the 'remove()' method. 'del' removes an element by its index, while 'remove()' removes the first occurrence of a specified value.

What is the difference between list.append(obj) and list.extend(seq)?

list.append(obj) adds the entire object 'obj' as a single element to the end of the list. list.extend(seq) iterates over the sequence 'seq' and appends each of its elements individually to the end of the list.

How do the len(), max(), and min() functions work with lists?

len(list) returns the total number of items in the list. max(list) returns the item with the highest value, and min(list) returns the item with the lowest value from the list.

Can these solutions help me prepare for my exams?

Yes, these solutions provide clear explanations and cover key concepts and methods related to lists in Python, which are essential for your Computer Science exams.

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