chapter 4

Question 1

1. What is []?

Answer 1

The empty list value, which is a list value that contains no items. This is similar
to how ‘’ is the empty string value.

Question 2

2. How would you assign the value ‘hello’ as the third value in a list stored in a variable named spam? (Assume
   spam contains [2, 4, 6, 8, 10].)

Answer 2

spam[2] = ‘hello’ (Notice that the third value in a list is at index 2 because
the first index is 0.)

Question 3

3. What does spam[int(‘3’ * 2) / 11] evaluate to?

For the following three questions, let’s say spam contains the list [‘a’, ‘b’, ‘c’, ‘d’].

Answer 3

3. ‘d’ (Note that ‘3’ * 2 is the string ‘33’, which is passed to int() before
   being divided by 11. This eventually evaluates to 3. Expressions can be used
   wherever values are used.)

Question 4

let’s say spam contains the list [‘a’, ‘b’, ‘c’, ‘d’].

4. What does spam[-1] evaluate to?

Answer 4

4. ‘d’ (Negative indexes count from the end.)

Question 5

5. What does spam[:2] evaluate to?

let’s say spam contains the list [‘a’, ‘b’, ‘c’, ‘d’].

Answer 5

5. [‘a’, ‘b’]

Question 6

let’s say bacon contains the list [3.14, ‘cat’, 11, ‘cat’, True].

6. What does bacon.index(‘cat’) evaluate to?

Answer 6

6. 1

Question 7

Q: 7. What does bacon.append(99) make the list value in bacon look like?

let’s say bacon contains the list [3.14, ‘cat’, 11, ‘cat’, True].

Answer 7

7. [3.14, ‘cat’, 11, ‘cat’, True, 99]

Question 8

bacon contains the list [3.14, ‘cat’, 11, ‘cat’, True].

Q: 8. What does bacon.remove(‘cat’) make the list value in bacon look like?

Answer 8

8. [3.14, 11, ‘cat’, True]

Question 9

9. What are the operators for list concatenation and list replication?

Answer 9

9. The operator for list concatenation is +, while the operator for replication is *.
   (This is the same as for strings.)

Question 10

10. What is the difference between the append() and insert() list methods?

Answer 10

10. While append() will add values only to the end of a list, insert() can add them
    anywhere in the list.

Question 11

11. What are two ways to remove values from a list?

Answer 11

11. The del statement and the remove() list method are two ways to remove
    values from a list.

Question 12

12. Name a few ways that list values are similar to string values. (jest ich 5 tutaj)

Answer 12

Both lists and strings can be passed to len(),

have indexes and slices,

be used in for loops,

be concatenated or replicated,

be used with the in and not
in operators.

Question 13

13. What is the difference between lists and tuples?

Answer 13

13. Lists are mutable(można je zmienić); they can have values added, removed, or changed. Tuples
    are immutable; they cannot be changed at all. Also, tuples are written using
    parentheses, ( and ), while lists use the square brackets, [ and ].

Question 14

14. How do you type the tuple value that has just the integer value 42 in it?

Answer 14

14. (42,) (The trailing comma is mandatory.)

Question 15

15. How can you get the tuple form of a list value? How can you get the list form of a tuple value?

Answer 15

15. The tuple() and list() functions, respectively

Question 16

16. Variables that “contain” list values don’t actually contain lists directly. What do they contain instead?

Answer 16

16. They contain references to list values.

Question 17

17. What is the difference between copy.copy() and copy.deepcopy()?

Answer 17

17. The copy.copy() function will do a shallow copy of a list, while the
    copy. deepcopy() function will do a deep copy of a list. That is, only
    copy. deepcopy() will duplicate any lists inside the list.