What is Python?

Python is a modern object-oriented programming language that’s well-suited for a variety of uses, from simple scripts to complex web applications. Using third-party tools, such as Py2exe or Pyinstaller, Python code can be packaged into standalone executable programs.

This Blog will be updated during my free time to share all the knowledge I learned in studing this powerful programming language.

Before we start make sure that you have the python installed in your computer, If you are using linux or mac chances are that you already have python preinstalled in your computer.

In this blog I’ll be using python 3, and sublime as my text editor. you can use what ever text editor you like such as eclipse to help you in you coding and compiling in one development application, but I prefer the traditional way of doing it using a separate text editor and command line it running python.

I will be starting this blog by creating the traditional hello world program.

#!/usr/bin/python3
print("Hello, World!")

to run python, save the file first with .py extension ex. helloWorld.py then you should compile it by typing in the terminal cat helloWorld.py then to run the program type in ./helloWorld.py if you got an Permission denied error type chmod 755 helloWorld.py to make it executable.

looking in the helloWorld.py the line #!/usr/bin/python3 is called shebang line, in unix based operating system such as linux and mackintosh, this is the path to the python interpreter which tells the computer to use it to run the program. while the print(“Hello, World”) is use to display the a text.

Assigning Values

a, b = 1, 2

1 will be assigned in “a”, and 2 will be assigned in “b”, so “a” will hold the value of 1 and “b” will hold the value of 2.

Conditional Statement

a, b = 1, 2

if a < b:
    print("a ({}) is less than b ({})".format(a, b))
else:
    print("a ({}) is not less than b ({})".format(a, b))

In creating conditional statement in python, you type the condition followed by colon then the indented code, this is how you create a block of codes in python, blocks are called “suites” in python. you can see this kind of syntax in loops, functions and classes. If you notice the curly braces inside the print statement, it will be replaced by the value inside the format. This format is a method of string object.

Conditional Expression

a, b = 1, 2

print("foo" if a < b else "bar")

This is the other way of creating conditionals in python

Working with loops There are two kinds of loops in python, the while loop and for loop.

While Loop

b = 1
while b < 50:
    print(b)
    b += 1

In creating while loop we type while followed by the condition then a colon, then underneath it we place the code we want to be done in this case print the value of b then followed by the incrementing value, in python the is no “++” e.g “b++” to increment the value by one, instead we can use “+=” sign to increment a value. In this example the print(b) will continue to execute until it reach 50, if we run the program we will see numbers 1 to 49, it will shows only up to 49 since the the increment happens after the print().

For Loop

fruits = ['banana', 'apple',  'mango']
for fruit in fruits:
    print('Current fruit :', fruit)

For loop works with iterator when the loop runs, it goes to each list inside the fruits variable and put it on the fruit variable one by one for each loop, it breaks out if it has no longer has a list to print.

Function

def loopValue(n):
    for num in range(1, n):
        print(num)

loopValue(20)
loopValue(30)

def is the keyword that we are defining a function and loopValue is the name of the function, a function can hold multiple parameter separated by commas, in this example (n) this holds the value that has been passed by calling the function “loopValue(20), loopValue(20)” this is a great way to reuse code preventing you to type them repeatedly.

<— TO BE CONTINUED —>