Chapter 5: Lists and Dictionaries
45 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the result of calling the sort method on a list?

  • It returns the sorted elements as a tuple.
  • It does not change the original list.
  • It alters the original list in place. (correct)
  • It returns a new list with sorted elements.

Which of the following methods is classified as a mutator method?

  • reverse (correct)
  • len
  • count
  • map

What value does a mutator method return upon execution?

  • It returns the original list.
  • It returns None. (correct)
  • It returns the length of the list.
  • It returns the modified list.

Consider the following list: example = [4, 2, 10, 8]. What will example look like after executing example.sort()?

<p>[2, 4, 8, 10] (A)</p> Signup and view all the answers

When comparing elements in a list for sorting, which operation is primarily used?

<p>both greater than (&gt;) and less than (&lt;) (C)</p> Signup and view all the answers

What is the primary difference between a list and a dictionary in Python?

<p>Lists allow manipulation of data values by position, while dictionaries associate data values with keys. (A)</p> Signup and view all the answers

Which of the following is a method that can manipulate a list in Python?

<p>append() (D)</p> Signup and view all the answers

In what scenario would a dictionary be preferred over a list?

<p>When you need to store data in pairs of related values. (B)</p> Signup and view all the answers

Which statement best describes the access of items in a list?

<p>Items must be accessed by their index values. (A)</p> Signup and view all the answers

What is a key characteristic of dictionaries compared to lists?

<p>Dictionaries associate values with unique keys. (D)</p> Signup and view all the answers

How do you define a simple function that returns a value in Python?

<p>def function_name(): return value; (D)</p> Signup and view all the answers

Which method would you use to remove an item from a list in Python?

<p>remove() (B), pop() (C)</p> Signup and view all the answers

What type of data can be stored in a list in Python?

<p>Any data type, including mixed types. (D)</p> Signup and view all the answers

What does the operator 'in' do when applied to a list?

<p>It checks if an element is present in the list (A)</p> Signup and view all the answers

When replacing an element in a list using the subscript operator, what is being referenced?

<p>An element’s position within the list (B)</p> Signup and view all the answers

What will be the output of 'print([1, 2, 3, 4])' in Python?

<p>[1, 2, 3, 4] (A)</p> Signup and view all the answers

What will the following code snippet produce? 'numbers = [2, 3, 4, 5]; for index in range(len(numbers)): numbers[index] = numbers[index] ** 2'

<p>[4, 9, 16, 25] (D)</p> Signup and view all the answers

What does the method L.append(element) accomplish?

<p>Adds element to the end of L (D)</p> Signup and view all the answers

Which statement about lists is true?

<p>Lists can have their elements added, removed, or replaced. (C)</p> Signup and view all the answers

If L contains 4 elements, which index would L.insert(index, element) place the element at if index is 5?

<p>4 (B)</p> Signup and view all the answers

What is the result of the operation 'words = sentence.split()' where sentence is 'This example has five words.'?

<p>['This', 'example', 'has', 'five', 'words.'] (C)</p> Signup and view all the answers

After executing 'for index in range(len(words)): words[index] = words[index].upper()', what will 'words' contain?

<p>['THIS', 'EXAMPLE', 'HAS', 'FIVE', 'WORDS.'] (A)</p> Signup and view all the answers

What would L.pop() return if L is currently [3, 5, 7]?

<p>7 (B)</p> Signup and view all the answers

Which of the following accurately describes L.extend(aList)?

<p>Adds the elements of aList to the end of L (B)</p> Signup and view all the answers

What happens if you attempt to access an index in a list that does not exist?

<p>You receive an IndexError. (D)</p> Signup and view all the answers

What happens when the L.insert(index, element) method is called with index less than 0?

<p>The element is added at index 0 (D)</p> Signup and view all the answers

How does L.pop(index) differ from L.pop()?

<p>It removes and returns the element at a specified index (B)</p> Signup and view all the answers

What will be the state of example after executing example.insert(1, 10) on the initial list [1, 2]?

<p>[1, 10, 2] (A)</p> Signup and view all the answers

If L contains [1, 2, 3] and L.pop(0) is executed, what will L be afterward?

<p>[2, 3] (C)</p> Signup and view all the answers

What does the method append do in a list?

<p>Adds a new element to the end of the list (D)</p> Signup and view all the answers

What is the result of using the extend method?

<p>Adds elements from another list to the end of the current list (A)</p> Signup and view all the answers

What happens if you try to find the index of an element that is not in the list using the index method?

<p>Raises an error (D)</p> Signup and view all the answers

What does the pop method do when called without an argument?

<p>Removes the last element from the list (B)</p> Signup and view all the answers

Which of the following gives the correct behavior of the in keyword when used with lists?

<p>Checks for an element's presence and returns True or False (B)</p> Signup and view all the answers

What is a defining characteristic of each item in a list?

<p>Each item has a unique index. (D)</p> Signup and view all the answers

What is the result of the following operation: example + [14, 15]?

<p>Creates a new list with elements of example followed by 14 and 15 (D)</p> Signup and view all the answers

What will be the contents of the 'example' list after executing example.pop(0)?

<p>[2, 10, 11, 12] (D)</p> Signup and view all the answers

Which of the following represents a valid list literal in Python?

<p>all of the above (D)</p> Signup and view all the answers

How can you create a list of integers from 1 to 4 in Python?

<p>both A and C (A)</p> Signup and view all the answers

What will the statement print when the target 45 is searched in aList = [34, 45, 67]?

<p>1 (B)</p> Signup and view all the answers

What does the len function return when applied to a list?

<p>The count of items in the list. (B)</p> Signup and view all the answers

What will the output be for the expression first[2:4] given first = [1, 2, 3, 4]?

<p>[3, 4] (A)</p> Signup and view all the answers

What is the correct output of the expression first + [5, 6]?

<p>[1, 2, 3, 4, 5, 6] (C)</p> Signup and view all the answers

When comparing two lists using the equality operator (==), what does it return?

<p>True if the lists have identical elements. (B)</p> Signup and view all the answers

Which of the following is NOT a method for creating a list?

<p>Using tuples. (B)</p> Signup and view all the answers

Flashcards

Python Lists

Ordered collections of items, allowing any data types.

Python Dictionaries

Unordered collections of key-value pairs.

List Items

Data elements within a list.

List Methods

Functions used to modify lists.

Signup and view all the flashcards

Dictionary Keys

Unique identifiers for each data value.

Signup and view all the flashcards

Dictionary Entries

Key-value pairs within a dictionary.

Signup and view all the flashcards

Appropriate Data Structure

Choosing the right structure (list or dictionary) for a task.

Signup and view all the flashcards

Data Organization

How data is arranged using lists and dictionaries.

Signup and view all the flashcards

How to print a list

To display the contents of a list, use the print() function with the list as an argument. For example, print([1, 2, 3]) will output [1, 2, 3].

Signup and view all the flashcards

Checking for element presence

The in operator determines if an element exists within a list. It returns True if found and False otherwise. Example: 3 in [1, 2, 3] is True.

Signup and view all the flashcards

Lists are Mutable

Lists are dynamic – their content can be changed after creation. You can add, remove, or replace elements.

Signup and view all the flashcards

Replacing an element

The subscript operator ([]) is used to access and modify individual elements in a list.

Signup and view all the flashcards

Replacing elements with squares

Using a loop, each element of a list can be replaced with its square.

Signup and view all the flashcards

Extracting words from a string

The split() method divides a string into a list of words, using spaces as separators.

Signup and view all the flashcards

Making words uppercase

The upper() method converts all characters of a string to uppercase.

Signup and view all the flashcards

Looping to modify words

You can use a loop to iterate through a list of words, applying the upper() method to each word individually.

Signup and view all the flashcards

append() Method

Adds an element to the end of a list.

Signup and view all the flashcards

extend() Method

Adds elements from another list to the end of the current list.

Signup and view all the flashcards

insert() Method

Inserts an element at a specific index in a list. If the index is greater than the list's length, it appends the element.

Signup and view all the flashcards

pop() Method

Removes and returns the last element of a list.

Signup and view all the flashcards

pop(index) Method

Removes and returns the element at a specific index of a list.

Signup and view all the flashcards

How do you add an element to the end of a list?

Use the append() method. For example, my_list.append(new_element).

Signup and view all the flashcards

How do you add elements from another list to a list?

Use the extend() method. For example, my_list.extend(another_list).

Signup and view all the flashcards

What does the insert() method do?

Inserts an element at a specific index in a list. If the index is greater than the list's length, it appends the element.

Signup and view all the flashcards

Append to a List

The append() method adds a single element to the end of a list.

Signup and view all the flashcards

Extend a List

The extend() method adds multiple elements from another iterable (like a list) to the end of a list.

Signup and view all the flashcards

Remove Last Element

The pop() method without an argument removes and returns the last element of a list.

Signup and view all the flashcards

Remove Specific Element

The pop() method with an index removes and returns the element at the specified index.

Signup and view all the flashcards

Check Element Presence

The in operator checks if an element exists in a list, returning True if found and False otherwise.

Signup and view all the flashcards

Find Element Position

The index() method returns the index of the first occurrence of an element in a list. Raises an error if the element is not found.

Signup and view all the flashcards

List Modification

Methods like append(), extend(), pop(), and index() allow you to modify the contents of a list.

Signup and view all the flashcards

List Immutability

While lists are mutable (changeable), using operators like + creates a new list without modifying the original.

Signup and view all the flashcards

Sorting a List

Arranging a list's elements in a specific order, often alphabetically or numerically.

Signup and view all the flashcards

List Sorting Method

The sort() method modifies a list by arranging its elements in ascending order.

Signup and view all the flashcards

Mutator Methods

Methods that modify the object they are called on, often with no return value.

Signup and view all the flashcards

Value None

The special value returned by mutator methods when they don't have a meaningful value to return.

Signup and view all the flashcards

What does aList.sort() return?

The sort() method modifies the list aList in place, so it returns None.

Signup and view all the flashcards

What is a Python list?

A Python list is an ordered collection of items. It can contain any data type like numbers, strings, or even other lists.

Signup and view all the flashcards

How do you create a list in Python?

You create a list using square brackets [] and separating items with commas. For instance, [1, 'apple', 3.14] creates a list with an integer, a string, and a float.

Signup and view all the flashcards

List Index

Each item in a list has a unique index, starting from 0 and going up to the number of items minus 1. The index tells you the position of an item in the list.

Signup and view all the flashcards

Accessing List Elements

You can access a specific item in a list using its index within square brackets. For example, my_list[1] gives you the second item (index 1) in my_list.

Signup and view all the flashcards

List Concatenation

You can combine two lists using the plus operator +. This creates a new list with all the items from both lists.

Signup and view all the flashcards

List Length

The len() function tells you the number of items in a list.

Signup and view all the flashcards

List Slicing

You can extract a portion (subset) of a list using slicing. This is done by specifying a starting and ending index (both optional) separated by a colon. my_list[1:3] extracts items from index 1 (inclusive) to index 3 (exclusive).

Signup and view all the flashcards

Study Notes

Chapter 5: Lists and Dictionaries

  • Lists are sequences of data values (items or elements)

  • List items can be of any type

  • Examples include shopping lists, to-do lists, rosters, guest lists, recipes, documents, and phone books

  • Each item in a list has a unique index specifying its position (starting from 0)

  • List Literals: Examples include ['apples', 'oranges', 'cherries'], [[5, 9], [541, 78]]

  • Lists can contain expressions to be evaluated, such as [x, math.sqrt(x)] when x = 2 becomes [2, 1.4142135623730951] or [x + 1] when x=2 becomes [3]

  • Lists of integers can be created using the range function, such as list(range(1, 5)) which becomes [1, 2, 3, 4]

  • The list() function can create a list from any iterable sequence. For instance, list("Hi there!") produces ['H', 'i', ' ', 't', 'h', 'e', 'r', 'e', '!']

  • Basic List Operators:

    • The len function, square brackets [] for accessing elements, the + operator for concatenation, and the == operator for equality all work as expected with lists
    • Examples - len(first) = 4, first[0] = 1, first + [5, 6] produces [1, 2, 3, 4, 5, 6], and comparing a list to another as in first == second

  • Printing Lists: To display list content, use the print() function. For instance, print([1, 2, 3, 4]) yields [1, 2, 3, 4]

  • in Operator (Membership Testing): The in operator checks if an element is present in a list. 3 in [1, 2, 3] is True, while 0 in [1, 2, 3] is False

Replacing an Element in a List

  • Lists are mutable. Elements can be changed
  • The subscript operator [] is used to replace elements, e.g., example = [1, 2, 3, 4]; example[3] = 0; example becomes [1, 2, 3, 0]
  • The index refers to an element's position within the list, not the list itself

List Methods (Inserting and Removing Elements)

  • append(e): Adds e to the end of a list
  • extend(aList): Adds elements in aList to the end of the list
  • insert(index, element): Inserts element at index (index) in the list. Inserts element at the end if index is out of bounds
  • pop(): Removes and returns element at the end of the list; returns None
  • pop(index): Removes and returns the element at index

List Methods (Continued)

  • append, extend, insert, pop, and sort fall under the category of "mutator methods" and typically don't return a value
  • Python commonly returns None with these methods
  • aList.sort() or print(aList.sort()) returns None

Searching a List

  • in operator: Checks for an element's existence in a list but does not return the element's position
  • index() method: Locates an element's position in a list. Raises an error if the element is not found.

Sorting a List

  • Lists are ordered by position – elements maintain their order.
  • The sort() method rearranges a list's elements based on natural ordering using "<", ">", and "=="
  • example = [4, 2, 10, 8]; example.sort(); example = [2, 4, 8, 10]

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Fundamentals of Python: First Programs PDF

Description

Explore the foundational concepts of lists and dictionaries in programming. This quiz covers list creation, indexing, and basic operations, along with practical examples. Test your understanding of how lists can store various data types and evaluate expressions.

More Like This

Python Data Structures Quiz
5 questions

Python Data Structures Quiz

FastGrowingHorse avatar
FastGrowingHorse
Python Basics and List Fundamentals
9 questions

Python Basics and List Fundamentals

IntelligentRainbow avatar
IntelligentRainbow
Computer Science Lecture 11-12
43 questions

Computer Science Lecture 11-12

EnviousEnlightenment2588 avatar
EnviousEnlightenment2588
Python List Operations Quiz
42 questions

Python List Operations Quiz

EliteCarnelian3565 avatar
EliteCarnelian3565
Use Quizgecko on...
Browser
Open
Browser
Browser