python

Question 1

reverse python string

Answer 1

txt = “Hello World”
txt = txt[::-1]
print(txt)

Question 2

Add list to class

Answer 2

class Person():
#self represents the object itself
def __init__(self, name):
self.name = name
self.books = []

def add_book(self, title):
    self.books.append(title)

Question 3

python used most often to _____

Answer 3

Websites, data analysis & visualization, task automation.

Question 4

Python is interpreted, meaning ____

Answer 4

it does not need to compile

Question 5

Python passes parameters by ____

Answer 5

reference by default, but also by value

Question 6

what is __init__

Answer 6

the first method of a class. when you instantiate an object it is automatically invoked to initialize members of a class.

Question 7

remove whitespace from string

Answer 7

string.strip()

Question 8

shuffle list

Answer 8

import random
random.shuffle(list1)

Question 9

what does break do?

Answer 9

breaks out of the current loop

Question 10

string slicing syntax

Answer 10

str[1:5]
index starts at 0, inclusive 1st field, exclusive 2nd field.

Question 11

class creation

Answer 11

class Person:
def sayHello(self):
print(“Hello”)

Question 12

create class instance and use method

Answer 12

p1 = Person()
p1.sayHello()

Question 13

define class function that takes a parameter

Answer 13

class Person:
def add_one(self, x):
return x + 1

print(p1.add_one(5))

Question 14

class init method purpose

Answer 14

method is called whenever an instance of it is created

Question 15

init method syntax

Answer 15

def __init__(self):
pass

Question 16

init method to create an object with a name by default

Answer 16

def __init__(self, name):
self.name = name

Question 17

getter method

Answer 17

def get_name(self):
return self.name

Question 18

setter method

Answer 18

def set_age(self, name):
self.name = name

Question 19

make classes that are connected to each other (add person to course)

Answer 19

class Course:
def __init__(self, name):
self.name = name
self.people = []

 def add_person(self, person):
      self.people.append(person)

Question 20

inheritance is used when?

Answer 20

When classes have a lot in common. You only need to hard code the different parts in the classes and inherit the similar code.

Question 21

how inheritance is implemented

Answer 21

You have subclasses take the parent class as a parameter. if Pet is the parent class and cat is a subclass, you’d do class Cat(Pet):

Question 22

overriding in inheritance

Answer 22

subclass functions will override parent class methods with the same name

Question 23

how to extend init in the parent class if you have an extra attribute you want to add (color)

Answer 23

if you have a Pet parent class with an init method that has a name parameter, the subclass will look like this:
class Cat(Pet):
def__init__(self, name, color):
super().__init__(name)
self.color = color

Question 24

what is a class attribute

Answer 24

something you can access using the name of the class.
class Person:
num = 0

print(Person.num)
# displays 0

Question 25

how to modify class attribute

Answer 25

you can assign a new value to it outside of the class. if you do Person.num = 5, and future person objects created after this will have a num of 5.

Question 26

class method syntax

Answer 26

@classmethod
def num(cls):
return cls.num()

Question 27

what does a class method do?

Answer 27

acts on the class itself. So you can keep track of changes to class attributes

Question 28

class method example

Answer 28

class Person:
number_of_people = 0
def __init__(self):
Person.add_person()
@classmethod
def add_person(cls):
return cls.num

Question 29

when are static methods used?

Answer 29

in a class which contains common functions, but without needing to create an instance of the class to use them.

Question 30

static method implementation

Answer 30

class Math:
@staticmethod
def add_one(x):
return x + 1

print(Math.add_one(1))
#displays 2

Question 31

what do static methods not do?

Answer 31

change anything