Lists

Question 1

What is the format for defining lists?

Answer 1

Lists are defined using the squared brackets [ ]

Question 2

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

Answer 2

You add an element to the end of a list by using the append method or using concatenation

my_list = [1, 2, 3]
my_list.append(4) OR my_list + [4] OR my_list += [4]
# my_list is now [1, 2, 3, 4]

Question 3

How can you extend a list with elements of another list?

Answer 3

You can extend a list with the elements of another iterable using the extend() method or the += operator.

my_list = [1, 2, 3], my_other_list = [4, 5]
my_list.extend([4, 5]) OR my_list += my_other_list

my_list is now [1, 2, 3, 4, 5]

Question 4

How do you add an element at a specific index?

Answer 4

You can insert an element at a specific index using the insert() method.

my_list = [1, 2, 3]
my_list.insert(1, 4)
# my_list is now [1, 4, 2, 3]

Question 5

How can you change an element at a specific index in a list?

Answer 5

You can update the value of an element at a specific index by assigning a new value directly to that index.

my_list = [1, 2, 3]
my_list[1] = 4
# my_list is now [1, 4, 3]

Question 6

What are the methods for removing elements from a list?

Answer 6

The methods for removing elements from a list are remove() pop() and del()

Question 7

How can you remove an element from a list at a specific point?

Answer 7

The remove() method removes the first occurrence of a specific value.

my_list = [1, 2, 3, 2]
my_list.remove(2)
# my_list is now [1, 3, 2]

Question 8

How do you return and remove an element from a list?

Answer 8

The pop() method removes and returns an element at a specific index.

my_list = [1, 2, 3]
popped_element = my_list.pop(1)
# my_list is now [1, 3] and popped_element is 2

Question 9

What method can be used to remove elements either by index or to clear an entire list?

Answer 9

The del() method can be used to remove elements by index or to clear the entire list.

my_list = [1, 2, 3]
del my_list[1]
# my_list is now [1, 3]

del my_list[:]
# my_list is now []

Question 10

What can be used to update multiple elements at once or to replace a portion of a list with another list?

Answer 10

You can use slicing to update multiple elements at once or to replace a portion of the list with another iterable.

my_list = [1, 2, 3, 4, 5]
my_list[1:4] = [10, 20, 30]
# my_list is now [1, 10, 20, 30, 5]

Question 11

How can List Comprehensions be used to update all elements in a list?

Answer 11

my_list = [1, 2, 3]
updated_list = [x * 2 for x in my_list]
# updated_list is [2, 4, 6]

Question 12

Lists are mutable. What does mutable mean?

Answer 12

Mutable means it can be updated.