Stuff

Question 1

How would you get the type of a value in Python?

Answer 1

Using the type() function.

Question 2

What is the difference between tuples and lists in Python?

Answer 2

You can not modify items in a tuple. In a list, you can.

Question 3

Why would you use a tuple?

Answer 3

1. More efficient in memory because it only uses the space it needs vs a list will allocate more that it needs because the size is unbound.

Question 4

What is this “ {2, 3, 4, 5} “ in Python?

Answer 4

This is a Set. (Data Structure)

Question 5

What is this “ (3, 0, ‘UM’) “ in Python?

Answer 5

This a Tuple. (Data Structure)

Question 6

What is this “ [ ‘app’, ‘tiger’, ‘pen’] “ in Python?

Answer 6

This is a List. (Data Structure)

Question 7

What is this “ { ‘name’: ‘Joe’, id: 4994} “ in Python?

Answer 7

This is a Dictionary, (Data Structure)

Question 8

What does this “ ** “ do in Python?

Answer 8

This is the exponent arithmetic operator.
EX: 2 ** 3 -> 8

Question 9

What does this “ // “ do in Python?

Answer 9

This is a division arithmetic operator that will give you an integer as a result rather than a float.
EX:
4 // 2 -> 2
4 / 2 -> 2.0

Question 10

What does this produce?
‘Hello’ * 3

Answer 10

‘HelloHelloHello’

Question 11

What do these Logical operators do?
- and
- or
- not

Answer 11

• and is used when you need both items to be true.
  and is like && in JS
• or is used when you need either item to be true.
  or is like || in JS
• not is used on 1 operator and is used to flip the truth/false value
  not is like the bang op. “!” in JS.
  not True -> False

Question 12

What do these Membership Operators do?
in
not in

Answer 12

These check to see if an item is in or not in a string and or data structure.
Ex.
‘a’ in ‘apple’ -> True
‘toy’ not in [‘car’, ‘bike] -> True

Question 13

How would you write a for loop in Python for this list?
my_list = [ 1, 2, 3, 3 ]

Answer 13

for num in my_list:
print(num)

Question 14

How would you write a while loop Python for this list?
my_list = [ 1, 2, 3, 3 ]

Answer 14

i = 0
while i < my_list.len():
print(my_list[i])
i += 1

Question 15

What does the __init__() function do?

Answer 15

This is called when a Class is initialized. It sets up the class with values based on what we define.
EX

class Dog:
    def \_\_init\_\_(self):
        self.name = 'Danny'
        self.legs = 4

Question 16

Assuming a Dog class exists, what is the type that this statement returns?

type(Dog(‘Rover’))

Answer 16

Dog. It will return the name of the class.

Question 17

What does this do?
int(8.99999)

Answer 17

Returns 8.
This is called casting from a float to an int. Python will not round this for you, it just takes away all decimal places.

Question 18

What do the following do?
round(10 / 3)
round(10 / 3, 2)

Answer 18

round(10 / 3) -> 3
round(10 / 3, 2) -> 3.33

This is the round class that Python has built in. It rounds your floats for you. The 2nd arg is optional and allows you to define how many decimal places you want.

Question 19

What does 1.2 - 1.0 return and how would you adjust the return?

Answer 19

It returns 0.19999999996 because python uses approximation for floats and could give unexpected results.

To fix this you could do the following:
round(1.2 - 1.0, 2) -> 0.2

Question 20

How would you grab just the first name below?
name = ‘Jim Jones’

Answer 20

name[0:3] -> Jim
or
name[:3]

Question 21

How would you grab just the last name below?
name = ‘Jim Jones’

Answer 21

name[4:]

Question 22

What are the 2 ways to combine the the strings below?

name = ‘Deek’
id = 22

Answer 22

1. name + ‘-‘ + id
2. f’{name}-{id}’ –This is the f string. It is like a template literal in JS.

Question 23

How would you create a multi-line string?

Answer 23

By using triple quotes.
EX.

'''
Dear Allen,
Hi.
-Ray
'''

Question 24

What is this?
b’\x00\x00\x00\x00’

Answer 24

A bytes object

Question 25

What will my_list look like after the code below? my_list = [0, 1, 2, 3, 4, 5] my_list = my_list[::2]

Answer 25

[0, 2, 4] the third number in the list slicing is saying how much do you want to slice by. In this situation it skips over by 2.

Question 26

What does range() do and how can you use it?

Answer 26

It creates a range of integers. ex: ``` for i in range(10): print(i) my_list = list(range(10)) --> [0, 1, 2, ...] ```

Question 27

What does the LIST.append() do?

Answer 27

This adds the given value to the end of a list

Question 28

What does the LIST.insert() do?

Answer 28

This inserts a value at a given index. EX ``` my_list = ['cat', 'dog', 'cow] my_list.insert(1, 'pig') -> ['cat', 'pig', 'dog', 'cow'] ```

Question 29

What does the LIST.remove() do?

Answer 29

It removes the given value from the list and throws an error if the item does not exist.

Question 30

How would you delete an item in a set?

Answer 30

my_set.discard('item')

Question 31

How would you get the keys and values from a Dictionary in Python?

Answer 31

my_dict.keys() my_dict.values()

Question 32

What are 2 of the ways you can access a value in a Dictionary?

Answer 32

my_dict.get('key') my_dict['key']

Question 33

What does the this block of code return? And what is it called? ``` myList = [1,2,3,4,5] [2*item for item in myList] ```

Answer 33

[2, 3, 6, 8, 10] This is called List Comprehension. It is looping over the list and making a copy of it with new values that are 2 * the originals.

Question 34

What does this block of code return? ``` myList = list(range(10)) filteredList = [item for item in myList if item % 2 == 0] filteredList ```

Answer 34

[0, 2, 4, 6, 8, 10]

Question 35

What does this block of code do? ``` amounts = ['22.99', '1.99', '3.22'] def addDollarSign(price): return '$' + price [addDollarSign(price) for price in amounts] ```

Answer 35

This is iterating over the amounts list and anding a dollar sign to the front of each. This is similar to .map() in JS.

Question 36

What does the pass statement do in Python?

Answer 36

It is a null statement. The interpreter doesn't ignore it, it just reads it as a no operation. Good for a function definition that you want to define later and just put a place holder in temporarily.

Question 37

What do *ags and **kwargs do in a Python function? Ex: ``` def my_func(*args, **kwargs): do stuff ```

Answer 37

*args allows you to have an unlimited amount of arguments. Then you can access them inside of your function as a tuple. **kwargs allows you to have an unlimited amount of keyword args. You can access them inside of your function as a dictionary. EX: ``` def my_func(*args, **kwargs): print(args) print(kwargs) my_func(1, 2, 3, name='tom', city='atlanta') output (1, 2, 3) {name: 'tom', city:'atlanta'} ```

Question 38

What does Try/Expect do?

Answer 38

It allows you to handle errors cleanly. Example: ``` def causeError(): try: return 1/0 except Exception as e: return e causeError() output: ZeroDivisionError('division by zero') ```