Python Coding for Teenagers

About Python

  • Python is a multi-paradigm programming language; Object Oriented and Procedural among others

Python Programming Environment Setup

First step is to set up the development environment.

You will need to download Python form here: http://www.python.org

What is a Variable?

A variable is a container where data is stored.

The data can be of any type.

Below you will find the definition of different data types.

Note: Unlike some other programming languages like Java in Python you do not have to declare the variable types.

Integer

A variable of type int is used to store integral values such as 1, 105 and 0.

Example

age = 12
length = 300

Float or Floating Point Number

A variable of type Float is used to store decimal numbers such as 1.4, 293.29 and -1322.76.

Example

temperature = 18.5

Boolean or bools

A Boolean data type can hold one of two values:

  • True
  • False

Example

result = "True"

String

A String data type holds a collection of characters known as a string.

Example

name = "Tom"
colour = "Green"

Printing Data Types with Python

The print() function is used for printing data types.  More on functions later.

Example

print "Python Programming is fun!"

Alternatively , you may want to store the string value in a variable and then print its value.  In both cases “Python is cool!” will be printed in the output console.

Example

myString = "Python Programming is fun!"
print myString;

Operators

Simple Assignment

Simply put, the assignment operator assigns a value to a variable.

Example

temperature = 35

After the above assignment, temperature variable holds a value of 35

Note that the value assigned can be changed later.  In which case, the variable will hold the new value.

here we say:

temperature = 40

The variable now holds a value of 40.

Compound Assignment

a += bis equivalent to a = a + b
a -= bis equivalent to a = a – b
a *= bis equivalent to a = a * b
a /= bis equivalent to a = a / b
a **= bis equivalent to a = a **b
a %= bis equivalent to a = a % b

Compound assignment operators can seem confusing at first because in mathematics you cannot add two numbers and assign the result to one of those numbers.

This is why it is important to understand the concept of VARIABLE!

A VARIABLE can be thought of as a box or a container that holds a value.  It is in effect space in memory that holds a value.

Here we have two variables: a and b

a = 1
b = 2
a = a + b

a was initially holding the value 1. We then execute a + b and assign the result to a.

a now holds the value 3.

Variable = Box that holds a value = Container that holds a value = Space in memory that holds a value

Arithmetic Operators

Arithmetic operators are used for mathematical calculations.

Addition (+), Subtraction (-), Multiplication (*) and Division (/)

((4 + 5 - 6) * 7 / 5)

Power (**)

3 ** 3

This is equivalent to 3 to the power of 3 and will return 27.

Modulus (%)

a % b will return the remainder of a/b

14 % 4

14/4 returns 3 with a remainder of 2.  Therefore 14 % 4 returns 2.

Comparison Operators

The comparison operators returns a boolean.

In other words they return True or False.

Syntax

a == b
a < b a > b
Note

In Python, strings can also be compared for equality and ordering using the comparison operators.