Chapter 9 Key Terms

Question 1

Dictionary

Answer 1

Object that stores a collection of data.

Question 2

key

Answer 2

Identifier for a value. They are used to access, modify, or add values.

Question 3

value

Answer 3

The data associated with or within a key, are typically numbers, lists, strings, and can even be other dictionaries.

Question 4

Syntax for Creating a Dictionary

Answer 4

dictionary =
{key1:val1, key2:val2}

Question 5

Syntax for Retrieving a Value from a Dictionary

Answer 5

dictionary[key]

Question 6

in

Answer 6

Is used to check if a key exists in a dictionary.

Question 7

not in

Answer 7

Is used to check if a key does not exist in a dictionary.

Question 8

Syntax for Adding Elements in a Dictionary

Answer 8

dictionary[key] = value

Question 9

del

Answer 9

Is used to remove an element.

Question 10

len

Answer 10

Is used to obtain a number of elements.

Question 11

Data Types in a Dictionary

Answer 11

Data types such as integers, strings, lists, other dictionaries, etc.

Question 12

Syntax for Creating an Empty Dictionary

Answer 12

empty_dict = {}

Question 13

clear

Answer 13

Is used to remove all items from a dictionary.

Question 14

get

Answer 14

Gets a value associated with a specified key.

Question 15

items

Answer 15

Returns all the dictionary keys and associated values.

Question 16

keys

Answer 16

Returns all the dictionary keys as a sequence.

Question 17

pop

Answer 17

Returns value associated with the specified key and removes that key-value pair from the dictionary.

Question 18

popitem

Answer 18

Removes and returns a random key-value pair from the dictionary.

Question 19

values

Answer 19

Returns a list of values in the dictionary.

Question 20

Dictionary Comprehension

Answer 20

An expression that reads a sequence of input elements and uses those input elements to produce a dictionary.

Question 21

if clause with Dictionary Comprehension

Answer 21

Used to select only certain elements of the input sequence.

Question 22

Set

Answer 22

An object that stores a collection of data in the same way as a mathematical set.

Question 23

Syntax for Creating a Set

Answer 23

my_set = {1,2,3}

Question 24

len and Set

Answer 24

len is used to get the number of elements in a set.

Question 25

Syntax for Adding and Removing Elements in a Set

Answer 25

my_set.add ()
my_set.remove ()

Question 26

in, not in, and Sets

Answer 26

in and not in are used to check if an element is present within a set.

Question 27

union

Answer 27

Is used to combine two sets; and contains elements of both sets.

Question 28

|

Answer 28

An operator is used to help find the union of two sets.

Question 29

intersection

Answer 29

A set that contains only the elements in both sets.

Question 30

difference

Answer 30

A set that contains the elements that appear in the first set but do not appear in the second set

Question 31

symmetric_difference

Answer 31

A set that contains elements not shared by the two sets.

Question 32

issubset

Answer 32

Checks if one set is a subset of another.

Question 33

issuperset

Answer 33

Checks if one set is a superset of another.

Question 34

set2 <= set1

Answer 34

Checking if set2 is a subset of set1.

Question 35

set1 >= set2

Answer 35

Checking if set1 is a superset of set2.

Question 36

Set Comprehension

Answer 36

A concise expression that creates a new set by iterating over the elements of a sequence.

Question 37

Serializing Objects

Answer 37

Convert the object to a stream of bytes that can easily be stored in a file.

Question 38

open

Answer 38

Is used to open files for reading and writing.

Question 39

dump

Answer 39

Is used to serialize an object and save it to a file using the pickle module.

Question 40

close

Answer 40

Is used to close a file.

Question 41

load

Answer 41

Is used to deserialize an object from a file using the pickle module.