Python Courses

After going through the introduction to python, the next important aspect is why to learn it. Well, programmers usually prefer working with Python due to the increased productivity it offers. When you aim to work on any python project, whether it's for python for beginners or advanced users, you must first be clear with the purpose. This implies that you must first clear the fundamentals of python by referring to the python tutorial for beginners.  So, after you learn python, you should have a clear perspective on why to learn python.

The following points justify the reasons to learn python:

• It lacks a compilation step, so the edit-test-debug cycle is quite fast.

• Debugging Python programs is straightforward. The debugger is written within Python, which affirms Python's wistful power.

• Python syntax is easy to learn and code and is very readable. The syntax has fewer lines of code than in other programming languages.

• Python is beneficial for various applications like python for data science, developing web applications, rapid application development, etc.

• It can seamlessly work on various platforms (like Windows, Linux, Mac, Raspberry Pi, etc.).

• It runs on an interpreter system, so code can run as soon as it is written, which leads to rapid prototyping.

• Python supports various popular libraries, including PyTorch, SymPy, Scikit-Learn, Pandas Python, PyBrain, TensorFlow, Matplotlib, etc.

• Python Machine learning programs are prevalent due to the support for various Python machine learning libraries and simple syntax.

Python Installation on Windows:

Once you install it on Windows, you can implement various python programs for practice. Before proceeding with python programming for beginners, you must know the installation procedure of Python, which consists of two parts:

Download and Installation of Python for Windows from the official website

Installing an IDE (PyCharm)

Part-1: Downloading and Installing Python from the official website:

 Follow the below steps to download and install Python from the official website.

Step-1: Firstly, open this link and click the ‘Download Python 3.7.2’ button.

Step-2: In this step, you may be asked for a location to save your life. Choose a suitable location (you can create a new folder named Python-3.7.2 in a C drive and click on the ‘Save’ button.

Step-3: Now double click the downloaded .exe file and choose the ‘Add Python 3.7’ to the PATH checkbox located below. This is to ascertain that it automatically gets added to the Windows Environment variable. If you don’t do that, you need to manually do it later. After the box is checked, you have to click on ‘Install Now’.

Step-4: During the installation process, the pop-up will be shown to indicate the installation process is in progress.

Step-5: After the setup completes, you will see a message on the screen. Simply click on the ‘Close’ button to complete the installation process.

Step-6: Finally, once it is installed, open the Windows search bar and type Python. Consequently, you will find a desktop app ‘Python 3.7 (32-bit)’. So, click on that and a command prompt will be shown.

Step-7: In the command prompt, you can write your first Python program, for example, print ‘Python Installation completed’.

 Part-2: Installing PyCharm:

This part involves installing PyCharm, one of the most demanding Integrated Development environments among Python programmers. Follow the below steps:

 Step-1: Firstly, you need to download and install the Community edition of PyCharm from here. Now click on the ‘Download button’ present below the Community.

Step-2: Just like we did in Part 1, we can choose the download location to save the life and then click on the downloaded .exe file. So, now you need to browse to the location where you prefer the installation of PyCharm IDE (the best python ide) and click on ‘Next’.

Step-3: In this step, you can create a Desktop Shortcut if desired and choose a 32-bit/64-bit launcher, depending on your system’s processor.

Step-4: Keep selecting JetBrains in the Start Menu Folder and click ‘Install’.

Step-5: The installation process continues. Once completed, it will prompt with a message screen.  The screen will then show the Run PyCharm Community Edition box (related to jetbrains pycharm). Then click on the ‘Finish’ button.

Step-6: Now, your Python IDE will launch.

Python Installation on Mac:

Prerequisites:

• macOS

• Log in as an administrator on terminal

Follow the below steps:

Step-1: Firstly, you have to check the python software version available on the system.

Step-2: Type the below command in the command prompt window:
$ python –version

Step-3: Check what version it shows. (Usually, it shows 2.7.10 installed on your system, so you can proceed with installing Python 3.6.3)

Step-4: To install python software 3.6.3, you need to download the latest version of Python from its official website. The file will then be downloaded in the .pkg format, and it can be downloaded directly through the Installer command.       
           

Step-5: No mounting is needed if the downloaded file is in .pkg format. Now you can use the installer command to install Python 3.6.3.

Type the following command in the command prompt:

$sudo installer –pkg downloads/python-3.6.3-macosx10.6.pkg –target /

Step-6: Note that because the installer is used with superuser permissions, the sudo forces the terminal to prompt the user to fill in the admin password. So, this process installs the Python 3.6.3 version to the root directory. This directory is mentioned with the target option.

Step-7: In this step, you need to verify Python3. To check the Python version running on your system, use the below command:

 $python –version command.

Python 3 Installation on CentOS:

Prerequisites:

• CentOS

• Login as an administrator on the terminal

• Yum should be configured on the system

 Follow the steps below:

Step-1: Firstly, you need to install the IUS community Repository that offers extra packages for Enterprise Linux. Implement the below command to install the IUS community repository.

$ sudo yum -y install

Step-2: Now run the following command to install Python 3.6 on your CentOS system.

$ sudo yum install python36u  

Step-3: To verify the installed version of Python, type the below command on the terminal.

python3.6 -V

To get started with Python programming, you need to step in by creating a new Python project. One of the python basic programs is python hello world printing. It serves as one of the best python programs for practice. Follow these simple steps:

• Firstly, you must create a new folder, ‘helloworld’.
• Now launch the VS code and then open the helloworld folder.
• Create a new app.py file, run the following code, and then save the file. 

print('Hello, World!')

Code language: Python (python)

Note: print() is the built-in function that displays a message on the screen. For our python examples, it will show 'Hello, Word!'

To run the app.py file, firstly, you need to launch the Command Prompt on Windows, Linux, or macOS.

Navigate to the HelloWorld folder.

Type the below command to run the app.py file:

python app.py

Code language: Python (python)

If there are no errors in your code, you will see the below message on screen:

Hello, World!

Code language: Python

Variable is a name used to refer to a memory location. The alternate name of the Python variable is an identifier, and it is used to store values. When programming in Python, you need not mention the variable type since Python is a infer language and is wise enough to determine the variable type.

Note that variable names can be a group of both digits and letters. However, they must begin with an underscore or a letter. Moreover, it is recommended to use lowercase letters when naming a variable. For example, computers and computers are treated as two different variables. You can practice python by first clearing the concept of variables.

How to declare a variable and assign values:

Python doesn’t bind the users to declare a variable before using it. It lets you create a variable when required. It is not necessary to explicitly declare a variable in Python. The particular variable is automatically declared whenever we assign a value to the variable.

The equal (=) operator assigns a value to a variable.

Let’s understand with one of the python examples:

print("System") 

Output:       

System

You can also assign a value to a variable, for example,

a = 10

print(a") 

Output:       

a = 10

Variable Names:

By now, you will be familiar with how to declare a variable in Python. The variable names can have lower case, uppercase, digit, and underscore characters (_).

Let’s consider the below example of the valid variable names:

name = "John" 

age = 25 

marks = 75 

print(name) 

print(age) 

print(marks) 

Output:

John

25

75

Python Variables are of two types:

• Local Variable
• Global Variable

Local Variables:

They are declared within the function and have scope in that function.

Here is one of the python programming examples for local variables:

def add(): 

x = 10 

y = 20 

z = x + y 

print("The sum is:", z) 

add() 

Output:

The sum is: 30

In this code, we have declared a function add() and assigned x and y variables in that function. Since these are local variables, they will have scope within this function only. If you attempt to use the exterior of the function, you will see an error.

Let’s try to use the variables outside the scope of the function:

add() 

print(a) 

Output:

The sum is: 30

print(a)

NameError: name 'x' is not defined

As seen from the above code, we get the NameError because the variable x is defined outside the function.

Global Variables:

Global variables have scope throughout the program. You can use them inside or outside the function.

Any variable declared outside the function is by default considered the global variable. Python lets you declare the global variables using the global keyword inside the function. But if you don’t use the global keyword, that function considers it as a local variable.

Here is one of the python programming examples for global variables:

a = 50

  def mFunction(): 

global a

print(a) 

a = 'Python programming ' 

print(a) 

mFunction() 

print(a) 

Output:

50

Python programming

Python programming

In the above code, we’ve declared a global variable ‘a’ and assigned a value to it. Subsequently, we defined a function and also accessed the declared variable through the global keyword within the function. It is possible to alter its value. Subsequently, we’ve assigned a new string value to the variable ‘a’. A function is called and then the print command is executed. Finally, it prints the value as a newly assigned value of ‘a’.

In Python, Strings are enclosed by either single or double quotation marks. So, ‘world’ is the same as “world”.

The print() function is used to show a string literal.

For example,

print("Hi")

Output:

Hi

How to assign a string to a variable:

To assign a string to a variable, you can use a variable name followed by an equal sign and the string.

For example, here is a simple python program to assign a string:

Example

a = "Hi"

print(a)

Multiline Strings:

A variable can be assigned with a multiline string with the use of three quotes:

Example:

a = """I am happy

print(a)

Alternatively, you can use three single quotes:

a = ‘’’I am happy

print(a)

In both the cases, the output is the same i.e. I am happy

Using Strings as Arrays:

Similar to several other popular programming languages, the Strings in Python can be used as arrays of bytes demonstrating unicode characters.

Python doesn’t support a character data type, so a single character is merely a string with a length:1.

You can use the square brackets to access elements of the string.

For example, if you want to obtain the character at position 1 of the string then Strings as Arrays can be used as,

x = "Dear Students!"

print(x[1])

Output:

e

String Length:

Use the len() function to obtain the length of the string:

x = "Students"

print(len(x))

Output:

8

Check String:

If you want to check if a specific phrase or character is available in a string then you need to use the ‘in’ keyword.

In the following example code, we will check if ‘old’ is present in the following text or not:

txt = "Old is Gold!"

print("Old" in txt)

You can implement Python syntax by directly writing in the Command Line. Here is a simple python program to do that.

>>> print("Good Morning!")

Output:

Good Morning!

Alternatively, you can create a python file on the server, through the .py file extension, and execute it in the Command Line:

C:\Users\Your Name>python newfile.py   
                        

Lists

Lists in Python are used to store multiple items within a single variable. They are created with the help of square brackets:

Example of python list: 

newlist = ["rose", "sunflower", "daisy"]

print(newlist)

Output:

"rose", "sunflower", "daisy"

Unique characteristics of Python List:

• List items are changeable, ordered, and allow duplicate values.
• In Python, List items are indexed; the first item denotes index [0], the second item denotes index [1], etc.

List Length:

To find out a number of items a list has, you can use the len() function:

The following example prints the number of items in the list:

newlist = ["rose", "sunflower", "daisy"]

print(len(newlist))

Output:

3

Tuples

Tuples in Python store multiple items in a single variable. Essentially, a tuple is an ordered and unchangeable collection.

They are written with round brackets.

Example to create a Tuple in Python:

newtuple = ("rose", "sunflower", "daisy")

print(newtuple)

Unique characteristics of Tuples in Python:

• Tuple items are unchangeable, ordered, and allow duplicate values.
• Tuple items are indexed; the first item denotes index [0], the second item denotes index [1], and so on.

 Dictionary:      

Dictionaries store data values in key: value pairs. In other words, a dictionary is a collection that is changeable, ordered, and doesn’t permit duplicates. They are written in curly brackets.

Example to create and print a dictionary in Python:

mydict = {

  "flower": "Rose",

  "color": "Red",

}

print(mydict)  

Output:

{'flower': 'Rose', 'color': 'Red'}

 Conditional Statements in Python:

List of Conditional Statements in Python:

Python If statement

Python If…else statements

Python Nested if statements

Python If-elif ladder

Python Short hand if statements

Python Short hand if-else statements

Now let’s understand each of them:

Python If statement:

It denotes the simple decision-making statement. In it, when you run some lines of code, a block of statement will execute if the condition is true else it will not be executed.

Syntax:

if (condition):

# if block

Python If…else statements:

In the If..else statement, there are two blocks. If the condition is false, the statements in the else condition are executed.

Syntax:

if(condition):

# if block

else:

# else block

Python Nested if statements:

In Nested if statements, an if statement includes another if statement. This conditional statement is useful to check another condition within a condition. You can use it to check multiple conditions in a specific program.

Syntax:

If (condition1):

#statement to be executed if condition is true

If (condition2):

     # statement to be executed if condition is true

#end of nested if(condition2)

#end of if

#end of if (condition1)

Python If-elif ladder:

This condition statement is stepwise executed from top to bottom. When the if condition is true, then the if block will be executed else not. Subsequently, it checks if the elif condition is true then it would be executed else not. Finally, if none of the conditions are true, the statements in the else block will be executed.

Syntax:

if(condition):

#statement to execute if condition is true

elif(condition):

#statement to be executed if condition is false and elif is true

elif(condition):

#statement to be executed if both conditions are false and this elif condition is true

.

. else:

#statement to execute when all the conditions are false

 Python Short hand if statements:

The alternate name is ‘one line statement’. In python, you can write an if statement, if else statement, and elif statement in a single line without indentation. You can use a short hand if statement if a single line statement needs to be executed.

Syntax:

If condition: statement               

Python Short hand if else statements:

This statement is helpful to write if else in a single line.

 Syntax:

if (condition): # if statement

else: #else statement

Loops      

A loop statement executes a statement or collection of statements multiple times. Three types of loops in Python are for loop, while loop, and nested loop.

for loop:

It executes a series of statements multiple times and condenses the code that deals with the loop variable.

while loop:

It iterates a statement or collection of statements while a given condition is ‘True’. Before executing the loop body, it tests the condition.

nested loops:

You can use a single or multiple loops into any other for, while, or do..while loop.

A lambda function in Python is a tiny anonymous function. It can accept any number of arguments; however, it has only one expression.

Syntax:

lambda arguments : expression

As per the syntax, the expression is executed and the result will be returned as,

lambda y: y

The expression includes lambda as a keyword, y as a bound variable, and y as a body.

Here is one of the python code examples for Lambda Function:

Let’s add 5 to argument y, and return the result:

x = lambda y : y + 7

print(x(5))

Python projects for beginners usually include the concepts of Objects and Classes. The Python classes and objects are fundamental concepts one must learn. Since Python is an object-oriented programming language, everything in this environment is an object along with its methods and properties.

 A Class behaves as an object constructor or an outline for creating objects.

How to create a Class in Python:

The keyword class helps to create a class.

Here is one of the python code examples for creating a class named MyClass, with a property named x: 

class NewClass:

  a = 10

Here, the NewClass is the class name and its property is named ‘a’.

How to create an Object in Python:

You can use NewClass to create objects:

Example:

Creating an object named m1, and print the value of a:

m1 = NewClass()

print(m1.x)

Output: 10

Python sets are mutable since we can add and delete elements into a set. However, sets can't hold mutable items.

So, the following code shows an error because the set internally uses a hashtable to store its elements. Hence, the particular set of elements must be hashable

Example code:

s = set([[1,2],[3,4,]])

Example of a mutable set in Python:

new_set = {1,2,3}

print(new_set)

print(id(new_set))

>>> {1, 2, 3}

>>> 2688892018248

Packages and Modules are not intended to extend your Python code over multiple directories and source files. They let you organise your code to reveal the logical structure of the thing your program attempts to do.

 3 ways to define a module in Python: