Lesson 1 · Full-Length Courses

Python for Beginners: A Practical Introduction

This lesson introduces core Python programming concepts using a Jupyter Notebook inside VS Code. You will learn variables, user input, type conversion,…

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CourseFull-Length Courses
Lesson1 of 7
Video35 min
FormatJupyter notebook · 26 code cells

What you'll learn

What Can You Do With Python?
Installing Python
Setting Up VS Code and Your First Notebook
Practice Exercise: Hospital Check-In
Practice Exercise: Basic Calculator
Practice Exercise: Weight Converter
Lists

Data

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Python for Beginners: A Practical Introduction#

This lesson introduces core Python programming concepts using a Jupyter Notebook inside VS Code.
You will learn variables, user input, type conversion, strings, arithmetic and comparison operators, if statements, loops, lists, and tuples.
By the end, you will be able to write small, working Python programs and understand the errors Python shows you along the way.

What Can You Do With Python?#

Python is a multi-purpose programming language used across many fields.
It is the leading language for machine learning and data science projects.
With the Django framework, Python powers major websites such as YouTube, Instagram, Spotify, Dropbox, and Pinterest.
Python is also widely used for automation, saving time by handling repetitive tasks.

Installing Python#

Head over to python.org and go to Downloads to get the latest version of Python for your operating system.
Run the installer. On Windows, make sure to check the box that says Add python.exe to PATH before clicking Install, since this lets your terminal and VS Code find Python.
On macOS, simply run the installer package and follow the prompts.

Setting Up VS Code and Your First Notebook#

Install Visual Studio Code from code.visualstudio.com.
Inside VS Code, open the Extensions view and install the Python extension and the Jupyter extension, both published by Microsoft.
Open the Command Palette with Control plus Shift plus P, type Create: New Jupyter Notebook, and press Enter.
In the top right corner of the notebook, click Select Kernel and choose your installed Python interpreter.

print('Hello World')

Hello World

age = 20
print(age)

age = 30
print(age)

price = 19.95
first_name = 'Alex'
is_online = True
print(price, first_name, is_online)

19.95 Alex True

is_online = false

---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
Cell In[5], line 1
----> 1 is_online = false

NameError: name 'false' is not defined

Practice Exercise: Hospital Check-In#

Imagine you are writing a program for a hospital checking in a new patient named John Smith, who is 20 years old.
Declare variables to store the patient's name, age, and whether they are a new patient, then print them out.

name = input('What is your name? ')
print('Hello ' + name)

Hello Alex

birth_year = input('Enter your birth year: ')
age = 2024 - birth_year
print(age)

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
Cell In[7], line 2
      1 birth_year = input('Enter your birth year: ')
----> 2 age = 2024 - birth_year
      3 print(age)

TypeError: unsupported operand type(s) for -: 'int' and 'str'

birth_year = input('Enter your birth year: ')
age = 2024 - int(birth_year)
print(age)

Practice Exercise: Basic Calculator#

Write a program that asks the user to enter two numbers, one at a time, allowing whole numbers or decimals.
Print the sum of the two numbers, labeled clearly, such as sum is 30.

first = float(input('First number: '))
second = float(input('Second number: '))
sum = first + second
print('Sum is ' + str(sum))

Sum is 30.5

course = 'Python for Beginners'
print(course.upper())
print(course.lower())
print(course.find('for'))
print(course.replace('Beginners', 'Everyone'))
print('Python' in course)

PYTHON FOR BEGINNERS
python for beginners
7
Python for Everyone
True

print(10 + 3)
print(10 - 3)
print(10 * 3)
print(10 / 3)
print(10 // 3)
print(10 % 3)
print(10 ** 3)

13
7
30
3.3333333333333335
3
1
1000

x = 10
x = x + 3
print(x)
x += 3
print(x)

13
16

x = 10 + 3 * 2
print(x)
y = (10 + 3) * 2
print(y)

16
26

print(3 > 2)
print(3 >= 3)
print(3 < 2)
print(3 <= 2)
print(3 == 2)
print(3 != 2)

True
True
False
False
False
True

price = 25
print(price > 10 and price < 30)
price = 5
print(price > 10 or price < 30)
print(not (price > 10))

True
True
True

temperature = 35
if temperature > 30:
    print('It is a hot day')
    print('Drink plenty of water')
elif temperature > 20:
    print('It is a nice day')
elif temperature > 10:
    print('It is a bit cold')
else:
    print('It is a cold day')
print('Done')

It is a hot day
Drink plenty of water
Done

Practice Exercise: Weight Converter#

Write a program that asks for a weight, then asks whether that weight is in kilograms or pounds, entering k or l.
Convert and print the weight in the other unit. Pounds to kilograms multiplies by 0.45; kilograms to pounds divides by 0.45.

weight = input('Weight: ')
unit = input('(K)ilograms or (L)bs: ')
if unit.upper() == 'K':
    converted = float(weight) / 0.45
    print('Weight in pounds is ' + str(converted))
else:
    converted = float(weight) * 0.45
    print('Weight in kilograms is ' + str(converted))

Weight in kilograms is 76.5

i = 1
while i <= 5:
    print(i)
    i = i + 1

i = 1
while i <= 10:
    print(i * '*')
    i = i + 1

*
**
***
****
*****
******
*******
********
*********
**********

Lists#

Numbers, strings, and Booleans are Python's primitive, or basic, data types.
Python also has complex data types built from these, and lists are one of the most common.
We use a list whenever we want to represent a collection of objects, such as a list of names or numbers.

names = ['John', 'Bob', 'Alex', 'Sam', 'Mary']
print(names)
print(names[0])
print(names[-1])
print(names[-2])
names[0] = 'Jon'
print(names)

['John', 'Bob', 'Alex', 'Sam', 'Mary']
John
Mary
Sam
['Jon', 'Bob', 'Alex', 'Sam', 'Mary']

names = ['John', 'Bob', 'Alex', 'Sam', 'Mary']
print(names[0:3])
print(names)

['John', 'Bob', 'Alex']
['John', 'Bob', 'Alex', 'Sam', 'Mary']

numbers = [1, 2, 3, 4, 5]
numbers.append(6)
print(numbers)
numbers.insert(0, -1)
print(numbers)
numbers.remove(3)
print(numbers)
print(1 in numbers)
print(10 in numbers)
print(len(numbers))

[1, 2, 3, 4, 5, 6]
[-1, 1, 2, 3, 4, 5, 6]
[-1, 1, 2, 4, 5, 6]
True
False
6

numbers = [1, 2, 3, 4, 5]
for item in numbers:
    print(item)

for number in range(5):
    print(number)
for number in range(5, 10):
    print(number)
for number in range(5, 10, 2):
    print(number)

numbers = (1, 2, 2, 3)
print(numbers.count(2))
print(numbers.index(3))

2
3

numbers = (1, 2, 3)
numbers[0] = 10

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
Cell In[26], line 2
      1 numbers = (1, 2, 3)
----> 2 numbers[0] = 10

TypeError: 'tuple' object does not support item assignment

Recap#

We covered variables, user input, and type conversion between strings, integers, floats, and Booleans.
We covered string methods, arithmetic, comparison, and logical operators, plus operator precedence.
We covered if, elif, and else for decision making, and while loops for repeating code.
We covered lists and tuples: creating them, indexing and slicing, adding and removing items, and iterating with for loops and range.
Practicing each exercise yourself in a Jupyter Notebook in VS Code is the best way to make these concepts stick.

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