Python Programming Tutorial
In this Python tutorial, you'll learn everything you need to start programming in Python. This tutorial is perfect for data science, machine learning, and web development. No prior knowledge in Python or programming is required as everything will be taught from scratch. I'm Mosh Hamadani, and I've taught millions of people how to code through this channel. If you're new here, make sure to subscribe as I upload new videos every week. Let's jump in and get started.
What is Python?
Python is a multipurpose programming language that can be used for a variety of different tasks, such as automation, web development, and data science.
- You can use Python in automation to automate repetitive tasks and save time and increase productivity.
- You need to install a code editor to write your own Python code.
- You can build amazing websites powered by Python.
We'll be using PyCharm as our code editor in this tutorial. When you open PyCharm for the first time, you have to configure a few settings, but we can skip that for now and set defaults. Let's create a new project and collapse the project window to give more space. We can then print a message on our application window.
Running Python Code
To run Python code in PyCharm, we go to the run menu and select run, or use the shortcut (ctrl+shift+r on a Mac). Then select the app to run, and the output will appear in the terminal window. Python is case sensitive so make sure to use the correct case when coding. We can declare variables, such as age and price, and assign them values. Python also has boolean values that can be true or false.
Now let's start coding!
age = 30
print(age)
price = 19.95
print(price)
Declare and Use Variables in Python
Here's a little exercise for you: imagine we want to write a program for a hospital, so we're going to check in a patient named John Smith. He's 20 years old and is a new patient. I want you to declare a few variables to store these values.
Use the comment section below to share your code.
Receiving User Input in Python
In Python, we have a built-in function called input() that we use to read a value from the terminal window. We can add a string argument to the function to prompt the user for input.
Let's write a simple program to demonstrate this:
name = input("What is your name? ")print("Hello, " + name)
When we run this program, it will prompt the user to input their name. Once a value is entered, the program will print the greeting message with the input value.
Data Types in Python
There are three main data types in Python: numbers, strings, and booleans.
- Numbers - This includes integers and floating-point numbers.
- Strings - This includes textual data.
- Booleans - This includes True and False values.
Converting Data Types in Python
Python has several built-in functions for converting the types of our variables. For example, we have the int() function for converting a value to an integer:
birth_year = "1982"age = 2020 - int(birth_year)print("You are " + str(age) + " years old.")
In the above example, we use the int() function to convert the birth_year string to an integer so we can subtract it from the current year.
We also have the float() function for converting a value to a float:
num = "10.5"float_num = float(num)print(float_num)
In the above example, we use the float() function to convert the num string to a floating point number.
Type Conversion in Python
In programming languages like Python, there are times when you need to convert a variable from one type to another. In this tutorial, I'll show you a bunch of cool things you can do with strings using Python for beginners.
In Python, the index of the first character in a string is 0. So, when we run this program, you're going to see 1 on the terminal because the index is 1.
print("Hello World"[1]) # Output: e
The float function is used to convert a string to a float value.
first = float(input("Enter the first number: "))
We can also change this expression to first + second, which is another way to write this piece of code.
The lower method is used to convert a string to lowercase or to find a character or a sequence of characters.
string = "Hello World"print(string.lower()) # Output: hello worldprint(string.find('o')) # Output: 4print(string.replace('o','a')) # Output: Hella Warld
The in operator can be used to check if a string contains a character.
string = "Python is a programming language for beginners."print('language' in string) # Output: True
Arithmetic Operators in Python
Python has various arithmetic operators that we can use, such as addition (+), subtraction (-), multiplication (*), and division (/).
print(10 + 3) # Output: 13
We also have an augmented assignment operator in Python that means incrementing a variable by a value.
x = 5x += 3 # Output: 8
Operator precedence in Python is similar to math, but we can always use parentheses to change the order of operations.
x = 10 + 3 * 2 # Output: 16
Multiplication and division have a higher order, so they are evaluated first. That's why the answer is 16.
x = 10 + 3 / 2print(x) # Output: 11.5
When we print x, we get 11.5.
x += 3print(x) # Output: 14.5
When we run x += 3, we get 14.5 as the result. When we run x == 13, it will store False in the x variable.
x = 1000 # Output: 1000
