chapter 9 practice questions: Lists

Question 1

What will the following print?

cheeses = [‘Cheddar’, ‘Edam’, ‘Gouda’]

print(‘Edam’ in cheeses)
print(‘Brie’ in cheeses)

Answer 1

1. True
2. False

Question 2

What is printed by the following?

alist = [4, 2, 8, 6, 5]
alist[2] = True

print(alist)

Answer 2

[4, 2, True, 6, 5]

Question 3

What is printed by the following?

alist = [3, 67, “cat”, [56, 57, “dog”], [ ], 3.14, False]

print(57 in alist)

Answer 3

False

Question 4

What will happen if you attempt to traverse an empty list?

Answer 4

Nothing will happen

Question 5

How many items are in this list?

nestedList = [[“First”, 2, [“Third”]]]

Answer 5

1

Question 6

What will the following print?

a = [1, 2, 3]
b = [4, 5, 6]
c = a + b
print(c)

Answer 6

[1, 2, 3, 4, 5, 6]

Question 7

What does the following print?

print([0] * 4)
print([1, 2, 3] * 3)

Answer 7

[0, 0, 0, 0]
[1, 2, 3, 1, 2, 3, 1, 2, 3]

Question 8

What will be printed by the following?

alist = [4, 2, 8, 6, 5]
alist = alist + 999
print(alist)

Answer 8

Error, you cannot concatentate a list with an integer

Question 9

What does the following print?

t = [‘a’, ‘b’, ‘c’, ‘d’, ‘e’, ‘f’]
t[1:3] = [‘x’, ‘y’]
print(t)

Answer 9

[‘a’, ‘x’, ‘y’, ‘d’, ‘e’, ‘f’]

Question 10

What is printed by the following?
alist = [4, 2, 8, 6, 5]
alist.append(True)
alist.append(False)
print(alist)

Answer 10

[4, 2, 8, 6, 5, True, False]

Question 11

what does .extend() do?

Answer 11

takes a list as an argument and appends all of the elements

Question 12

What does the following print?

t1 = [‘a’, ‘b’, ‘c’]
t2 = [‘d’, ‘e’]
t1.extend(t2)
print(t1)

Answer 12

[‘a’, ‘b’, ‘c’, ‘d’, ‘e’]

Question 13

what does .sort() do?

Answer 13

arranges the elements of the list from low to high

Question 14

True or False? The sort method alphabetizes lists

Answer 14

False

Question 15

what does .pop() do?

Answer 15

modifies the list and returns the element that was removed

Question 16

What happens when you don’t provide an index for .pop()?

Answer 16

If you don’t provide an index, it deletes and returns the last element.

Question 17

What is printed by the following?
alist = [4, 2, 8, 6, 5]
temp = alist.pop(2)
temp = alist.pop()
print(alist)

Answer 17

[4, 2, 6]

Question 18

What is the difference between del and .remove() ?

Answer 18

both are for removing an item in a list, but .remove() is used when you don’t know the index for an item

Question 19

What is the return value of .remove() ?

Answer 19

None

Question 20

Contrast sum() with len() and max()

Answer 20

sum() can only work when all the items in the string are numbers
len() and max() can work with other types that are comparable

Question 21

What does the following print?

s = ‘spam’
t = list(s)
print(t)

Answer 21

[’s’, ‘p’, ‘a’, ‘m’]

Question 22

what is .split()?

Answer 22

function to break a str into letters
the delimiter is where you want to split it
ex. .split(delimiter)

Question 23

What is printed by the following?

myname = “Edgar Allan Poe”
namelist = myname.split()
init = “”
for aname in namelist:
init = init + aname[0]
print(init)

Question 24

what is .join()?

Answer 24

opposite of .split(); concatenates the strs in a list
also uses delimter

Question 25

how to concatenate strings without spaces?

Answer 25

use empty str, ‘’ as delimiter in .join()

Question 26

What does the following print?

mylist = [‘Hannah’, ‘Grace’, ‘Olivia’, ‘Ruth’]
delimiter = ‘’
print(delimiter.join(mylist)

Answer 26

HannahGraceOliviaRuth

Question 27

When reading lines from a file, what list method can be used to select or print parts of a line?

Answer 27

split

Question 28

what is the ‘is’ operator used for?

Answer 28

To check whether two variables refer to the same object
ex.
a = ‘banana’
b = ‘banana’
print(a is b)

Question 29

What will the following print? Why?

a = [1, 2, 3]
b = [1, 2, 3]
print(a is b)

Answer 29

False; 2 lists are 2 different objects

Question 30

When two lists have the same elements, but are different objects we say they are __________?

Answer 30

equivalent

Question 31

Equivalent or identical?

a = [1, 2, 3] b = a

Answer 31

identical

Question 32

An object with more than one reference has more than one name, so we say that the object is ______?

Answer 32

aliased, they are mutable

Question 33

What is printed by the following?

alist = [4, 2, 8, 6, 5]
blist = alist
blist[3] = 999
print(alist)

Answer 33

[4, 2, 8, 999, 5]

Question 34

What does the following print?
def myfun(lst):
del lst[0]

mylist = [‘a’, ‘b’]
myfun(mylist)
print(mylist)

Answer 34

[‘b’]

Question 35

What is the difference between .append() and +?

Answer 35

.append() modifies the existing list, + creates a new object

Question 36

Does this function remove the head of the list? what does it do?

def bad_delete_head(t):
t = t[1:]

Answer 36

The slice operator creates a new list and the assignment makes t refer to it, but none of that has any effect on the list that was passed as an argument