6. Python

What does dynamically typed mean

Python is dynamically typed — types are determined at runtime, not declared in advance

Is python interpreted or translated

Python source code is executed line by line by an interpreter.

What paradigms does python support

Procedural, object oriented and functional styles

What is a REPL

Read - eval - print loop

Interactive interpreter where you type and run code one line at a time

What is semantic whitespace

indentation that defines code structure

What does python use instead of braces

Indentation

What does python use instead of semicolons

Nothing — statements end at the line break

How do you write a comment in python

# comment here

how do you find the type of a variable in python

type(x)

How is boolean true and false written in python

True and False

How do you cast data types in python

int(“5)

float(3)

str(42)

list(“abc”)

How do you create a list in python

empty = []
numbers = [1, 2, 3, 4, 5]
mixed = [1, "two", 2, 3.24, True, None]
nested = [[1, 2], [3, 4]]

how do you add items to a list in python

lst.append(x)

how do you insert items into a list

lst.insert(i, x)

i for index

x for data

how do you remove items from a list in python

list.remove(x)

removes first instance of x

How do you get the length of the list

len(lst)

how do you check if an item is in a list in python

x in lst

What is a tuple in python

A list that cannot be changed (immutable)

basically a const list

How do you create a dictionary in python

empty = {}
person = {"name": "Alice", "age": 30}
# like a list but with names

What is a set in python

An unordered collection of unique items

• removes duplicates

• has no order

How do you get the length of a string in python

len(string)

what actions can you perform on a string

s.upper()

s.lower()

s.strip() — removes leading / tailing whitespace

what does s.split(“,”) do

splits the data in the string (s), based on the identification of the delimiter (“,”). returns in a list

How can you concatenate with strings and variables

greeting = f"Hello, {name}"

what does an if statement look like in python

if score >= 70:
	grade = "distinction"
elif score >= 50:
	grade = "pass"
else:
	grade = "fail"

what does a while loop look like in python

while count < 10:
	print(count)
	count += 1

what does a for loop look like in python

for i in range(10):
	print(i)

what does loop control contain in python

break — exit loop

continue — skip to next iteration

how do you define a function in python

def add(a, b):
	return a + b

result = add(3, 5);

how do you define a class in python

class Car:
	def __init__(self, colour):
		self.colour = colour
		self.miles_driven = 0
	
	def drive(self, miles):
		self.miles_driven += miles
	
	def get_colour(self):
		return self.colour

how do you create an object in python

c = Car("white")
c.drive(100);

how does inheritance work in python

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

class Person(Mammal):
	def __init__(self, name, age):
		super().__init__(name)
		self.age = age

How does exception handling work in python

try:
	x = int(input("Enter a number:"))
	y = 10 / x
	print(y)
except ValueError:
	print("That wasn't a number")
except ZeroDivisonError:
	print("Can't divide by zero")
except Exception as e:
	prin("Error: {e}")