Python Tutorial for Beginners

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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:

Ubuntu

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:
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 import "mymodule" to use it with the syntax:
# Import module "mymodule" in package "org.o7planning.test"

import org.o7planning.test.mymodule
Or import 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:
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

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