Data Types - List

Question 1

What is the fastest and most memory-efficient way to generate a list of numbers

Answer 1

list(range(n))

Question 2

fruits = [“apple”, “banana”, “cherry”]

Give 3 ways to remove “bananna” from this list

Answer 2

del fruits[1]

fruits.pop(1)

fruits.remove(“banana”)

Question 3

a = [ ]
a += 15

What does the above return

Answer 3

TypeError

+= can be used to extend a String, List or Tuple, but 15 is an integer.

Further, for List only, .extend() gives the same result ( .extend() is specific to Lists)

Question 4

a = [ ]

Give the best way to add the integer 15 to list “a” as an item

Answer 4

a.append(15)

Question 5

a = [ ]

Extend List “a” by [15]

Answer 5

a += [15]

OR

a.extend([15])

Note: += is the same as .extend(), except += works with any iterable, .extend() only works with Lists

Question 6

a = [1, 3, 4]

Add the Integer 2 to List “a” between 1 & 3

Answer 6

a.insert(1, 2)

Syntax: .insert(index, item)
Result: a = [1, 2, 3, 4]

Question 7

for item in lst:
print(lst[item])

What does the above print

Answer 7

TypeError

This treats “item” like it’s an index, but it’s an item (in this case an item in “list”).

If you want to print the Item, it should be typed as below,

for item in list:
print(item)

Question 8

lst = [7,2,9,4,7,1,8,5,3]

Find the total of these numbers

Answer 8

sum(lst)

Question 9

lst = [1,2,3,4,5]

Give 2 ways of printing “5” from “lst”

Answer 9

print(lst[-1])

print(lst[4])

Question 10

lst = [1,2,3,4,5]

Print “1” from “lst”

Answer 10

print(lst[0])

Question 11

lst = [1,2,3,4,5]

what does each of the lines below print

lst[0]

lst[0:]

Answer 11

lst[0] = 0

lst[0:] = [1,2,3,4,5]

Question 12

lst = [1,2,3,4,5]

what does each of the lines below print

lst[-1]

lst[-1:]

Answer 12

lst[-1] = 5 # Integer

lst[-1:] = [5] # List