Python Tutorial for Beginners

Requirements
Create Project
Create your first module
Python Module and Python Package
Examples
Lookup Python Documentation

1. Requirements

Make sure that your computer has already installed Python and a tool (IDE) for Python programming (E.g: PyDev). If not, you can see the guides below:

Windows:

Install Python on Windows

Ubuntu

Install Python on Ubuntu

Install PyDev for Eclipse

2. Create Project

From Eclipse, let's select:

File/New/Other..

Use "Grammar Version" 3.x

Note: Here I use "Grammar Version 3.6", the Grammar Versions of Python are a bit different, you can see more at:
Conventions and Grammar versions in Python

Project was created.

3. Create your first module

On Eclipse select:

File/New/File

Enter name of file:

main.py

Add content to main.py:

main.py

print ("Hello Python!");

x = 5;
y = 10;
z = 20;

print (x + y + z);

Run the main.py file by right-clicking it and select:

Run As/Python Run

The result received when running main.py:

4. Python Module and Python Package

A Python module is simply a Python source file, which can expose classes, functions and global variables.

When imported from another Python source file, the file name is treated as a namespace.

A Python package is simply a directory of Python module(s).

Create a "package":

When you create a package named "org.o7planning.test", there are 3 folders created including "org", "o7planning", "test". Each of folders has a file already been created named "__init__.py". "__init__.py" folders have no content inside but they ask Python to treat the folders containing it as a "package".

You can create a module inside package, for example, I create a module named as "mymodule.py" inside the "org.o7planning.test" package:

And in another module, you can enter "mymodule" to use it with the syntax:

# Import module "mymodule" in package "org.o7planning.test"

import org.o7planning.test.mymodule

Or enter a class "myclass" in the "mymodule" module:

# Import a class in module.

from org.o7planning.test.mymodule import myclass

5. Examples

math is a module that is available in Python. It contains mathematical functions. To use it you need to import it. Here are some functions of this module:

Function	Description
math.floor(x)	Return the floor of x as a float, the largest integer value less than or equal to x.
math.fabs(x)	Return the absolute value of x.

See more functions of math:
https://docs.python.org/3.6/library/math.html

importExample1.py

# This will import math module
import math 

# math.floor(x)
# Return the floor of x as a float, 
# the largest integer value less than or equal to x.
print ("math.floor(100.12) : ", math.floor( 100.12) )

# Return the absolute value.
print ("math.fabs(-100.72) : ", math.fabs( -100.72) )

Create a module named "mymodule" and place it in the "org.o7planning.test" package. In the mymodule defines a function named sayHello.

NOTE: In this tutorial I do not introduce the details of the function. If you are beginner with Python, you do not need to worry about that.

mymodule.py

# Define a function, with one parameter
# and return a string.
def sayHello(name) :
    return "Hello "+ name

# Using sayHello function.
text = sayHello("Python")  

print(text)

Run mymodule:

In another module you want to use the sayHello function of "mymodule" you need to import this module, or just import the sayHello function of this module.

Import module:

importExample2.py

# Import module.
import org.o7planning.test.mymodule
 
# Call sayHello function of mymodule:
greeting = org.o7planning.test.mymodule.sayHello("Python")


print(greeting)

Import function:

importExample3.py

# Import sayHello function.
from org.o7planning.test.mymodule import sayHello

# Call sayHello function of mymodule:
greeting =  sayHello("Python")
 

print(greeting)

6. Lookup Python Documentation

Lookup Python documentation