Online Learning Platform
Python practice problems help beginners to become experts in a python programming language with a small amount of practice effort.
Write a Python program to create a directory with os.mkdir().
True
os.mkdir() creates one folder; it fails if it already exists.import os if not os.path.exists("reports"): os.mkdir("reports")print(os.path.isdir("reports"))True
New to this topic? Read the lesson, then come back.
Write a Python program to get the list of environment variables with os.environ.
True True
os.environ behaves like a dictionary.import os names = sorted(os.environ)print(len(names) > 0)print("PATH" in names)for name in names[:0]: print(name, "=", os.environ[name])True True
sorted() of the mapping gives the variable names.
The loop is limited to [:0] here on purpose: environment values often contain paths, user names and secrets, so print them only on your own machine.
New to this topic? Read the lesson, then come back.
Write a Python program to set an environment variable for the current process.
testing child sees: testing
os.environ; child processes inherit it.import osimport subprocessimport sys os.environ["APP_MODE"] = "testing"print(os.environ["APP_MODE"])child = subprocess.run([sys.executable, "-c", "import os; print(os.environ['APP_MODE'])"], capture_output=True, text=True)print("child sees:", child.stdout.strip())testing child sees: testing
The value lives only in this process and the processes it starts; it does not change system settings.
New to this topic? Read the lesson, then come back.
Write a Python program to get the current working directory.
1 True
os.getcwd() returns the folder the program runs in.import os cwd = os.getcwd()print(os.path.basename(cwd))print(os.path.isabs(cwd))1 True
The full path depends on your computer, so the example prints only the last folder name.
getcwd() always returns an absolute path.
New to this topic? Read the lesson, then come back.
Write a Python program to read an environment variable.
True development
os.environ.get(name, default) or os.getenv(name, default).import os print("PATH" in os.environ)print(os.getenv("APP_MODE", "development"))True development
APP_MODE is not set, so the default is returned instead of an error.
New to this topic? Read the lesson, then come back.
Write a Python program to get the median of all the elements of a list.
[2, 4, 6, 7, 5, 8, 3, 11]
[2, 3, 4, 5, 6, 7, 8, 11] 5.5 5.5
import statistics items = [2, 4, 6, 7, 5, 8, 3, 11]s = sorted(items)mid = len(s) // 2median = s[mid] if len(s) % 2 else (s[mid - 1] + s[mid]) / 2print(s, median, statistics.median(items))[2, 3, 4, 5, 6, 7, 8, 11] 5.5 5.5
Eight values, so the median is the average of the 4th and 5th sorted values, 5 and 6.
New to this topic? Read the lesson, then come back.
Create Dog (inherits Animal) with breed and weight, and a method to print all details.
Bruno is brown, a Labrador weighing 28 kg
show and reuse the parent’s message with super().class Animal: def __init__(self, name, color): self.name, self.color = name, color def show(self): return f"{self.name} is {self.color}" class Dog(Animal): def __init__(self, name, color, breed, weight): super().__init__(name, color) self.breed, self.weight = breed, weight def show(self): return super().show() + f", a {self.breed} weighing {self.weight} kg" print(Dog("Bruno", "brown", "Labrador", 28).show())Bruno is brown, a Labrador weighing 28 kg
New to this topic? Read the lesson, then come back.
Create Animal with name and colour and a method to print them.
Bruno is brown
class Animal: def __init__(self, name, color): self.name, self.color = name, color def show(self): print(f"{self.name} is {self.color}") Animal("Bruno", "brown").show()Bruno is brown
New to this topic? Read the lesson, then come back.
Create ShoppingCart with items and total cost, and methods to add and remove items and calculate the total.
{'pen': (10, 5)} 50class ShoppingCart: def __init__(self): self.items = {} def add(self, name, price, qty=1): old_qty = self.items.get(name, (price, 0))[1] self.items[name] = (price, old_qty + qty) def remove(self, name): self.items.pop(name, None) def total_cost(self): return sum(price * qty for price, qty in self.items.values()) cart = ShoppingCart()cart.add("pen", 10, 3)cart.add("bag", 650)cart.add("pen", 10, 2)cart.remove("bag")print(cart.items, cart.total_cost()){'pen': (10, 5)} 50Adding an item again increases its quantity instead of replacing it.
The total is calculated when needed, so it is always up to date.
New to this topic? Read the lesson, then come back.
Create EBook (inherits Book) with file_size and format, and methods to open and close the book.
Opened Python Basics (PDF, 3.4 MB) Closed Python Basics
class Book: def __init__(self, title, author, pages): self.title, self.author, self.pages = title, author, pages class EBook(Book): def __init__(self, title, author, pages, file_size_mb, fmt): super().__init__(title, author, pages) self.file_size_mb, self.format = file_size_mb, fmt self.is_open = False def open(self): self.is_open = True return f"Opened {self.title} ({self.format}, {self.file_size_mb} MB)" def close(self): self.is_open = False return f"Closed {self.title}" e = EBook("Python Basics", "SQA Tools", 220, 3.4, "PDF")print(e.open())print(e.close())Opened Python Basics (PDF, 3.4 MB) Closed Python Basics
New to this topic? Read the lesson, then come back.