Programming with Mosh
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. 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.
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