Dictionaries

Question 1

What is a dictionary?

Answer 1

A set of key value pairs. Keys are unique. They are mutable (can be changed).

Question 2

How can you retrieve the value from a dictionary?
bad_guys = {“batman”: “bane”, “daredevil”: “kingpin”, “x-men”: “apocalypse”}

who is batman’s bad guy?

Answer 2

bad_guys[“batman”]

will return:
“bane”

Question 3

what happens if you specify a key that is not in the dictionary?

Answer 3

KeyError

Question 4

How do you replace a value in the dictionary?
bad_guys = {“batman”: “bane”, “daredevil”: “kingpin”, “x-men”: “apocalypse”}

replace “apocalpyse” with “juggernaut”

Answer 4

bad_guys[“x-men] = “juggernaut”

Question 5

How can you delete a key in a dictionary?

bad_guys = {“batman”: “bane”, “daredevil”: “kingpin”, “x-men”: “apocalypse”}

delete batman

Answer 5

del bad_guys[“batman”]

Question 6

True or False - You can access dictionaries with index #s.

Answer 6

False. You cannot, you will get KeyError

Question 7

How do you call a specific list value within a dictionary?

amit_linkedIn = {‘fname’:’Amit’, ‘lname’:’Shah’, ‘past_jobs’: [‘gcg’, ‘om’, ‘psc’]}

Return OM

Answer 7

amit_linkedIn[‘past_jobs’][1]

Question 8

How do you call a specific dictionary value within a dictionary?

amit_linkedIn = {‘fname’:’Amit’, ‘lname’:’Shah’, ‘past_jobs’: [‘gcg’, ‘om’, ‘psc’], ‘transportation’:{‘car’:’subaru’, ‘subway’:’A’, ‘cab’:[‘uber’, ‘lyft’]}}

Return car

Answer 8

amit_linkedIn[‘transportation’][‘car’]

Question 9

True or False - Keys can be used more than once.

Answer 9

False

Question 10

True or False - dictionaries cannot be keys

Answer 10

True

Question 11

True or False - lists can be keys

Answer 11

False

Question 12

How can you check for the existence of keys within a dictionary?

amit_linkedIn = {‘fname’:’Amit’, ‘lname’:’Shah’, ‘past_jobs’: [‘gcg’, ‘om’, ‘psc’]}

Check for past jobs

Answer 12

> > > ‘past_jobs’ in amit_linkedIn
True

> > > amit_linkedIn.get(‘past_jobs’)
[‘gcg’, ‘om’, ‘psc’]

Question 13

What does the dictionary.get() function do?

Answer 13

It will provide you with the value for the key that is provided in the get function.

Question 14

What does the dictionary.items() function do?

Answer 14

It lists out the key value pairs in tuple form.

Question 15

What does the dictionary.keys() function do?

Answer 15

Lists out the keys

Question 16

What does the dictionary.values() function do?

Answer 16

Lists out the values

Question 17

What does the dictionary.pop(‘key’) function do?

Answer 17

removes the ‘key’ from the dictionary, while providing the value removed.

Question 18

What does the dictionary.popitem() function do?

Answer 18

removes a random key value pair from the dictionary, while providing the value removed.

Question 19

test = {“a”: “random”, “b”: “rigid”, “c”: “flexible”}

test.update(b=”solid”, c=”flexy”)

notice the = and lack of “ for the keys. What is the new value of test?

Answer 19

test = {“a”: “random”, “b”: “solid”, “c”: “flexy”}

Question 20

test = {"a": "random", "b": "rigid", "c": "flexible"}
test2 = {"b"="solid", "c"="flexy"}

test.update(test2)

what is the new value of test?

Answer 20

test = {“a”: “random”, “b”=”solid”, “c”=”flexy”}

Question 21

test = {"a": "random", "b": "rigid", "c": "flexible"}
test2 = {"b"="solid", "c"="flexy"}

test.clear()

what is the new value of test?

Answer 21

test = {}