## Python: Decision Making

Every day we make decisions. When I get up in the morning, I need my shake. Now, for the shake, I need 500 ml Milk, 100 gms of Oats, 1 Banana, 1 Kiwi, and 1 Apple. In case, I don’t have any one of these, it can spell trouble. What’s the trouble ? I cannot make my shake.

In programming, we have a similar structure to situations such as these. Decision making is done with a set of statements called if, else-if, and else.

If: If a certain condition is met, we perform a block of code.
Else-if: If the IF condition is not met, we perform the code written in else-if
Else: If the IF condition, and the ELSE-IF condition are both not met, we perform this block of code.

A more picturesque, and descriptive version can be seen in this image below: func.in: An image representing if-else statements. The order of preference is 1, 2, and then 3 .

#### IF statement

Example:

x = 33
y = 200
if y > x:
print(“y is greater than x”)

Output:

y is greater than x

Please note the indentation. In Python, we use indentations as a way of saying that the code which follows the statement is enclosed. In other programming languages, we tend to use braces, or a parenthesis for the same. In python, things are slightly simpler, and we use indentations.

#### ELIF statement

Example:

x = 56
y = 56
if x > y:
print(“x is greater than y”)
elif x == y:
print(“x and y are equal”)

Output:

x and y are equal

From the above example, we can see that because a and b both have equal values, the first block was not satisfied. Instead, the second block of code under elif, has been executed.

#### ELSE statement

Example:

x = 100
y = 50
if x > y:
print(“x is greater than y”)
elif x == y:
print(“x and y are equal”)
else:
print(“x is greater than y”)

Output:

x is greater than y

## Python: Operators

The heart, the soul, and the foundation of any programming language, are it’s operators. They help build the logic, and transform your ideas into functioning models. They can manipulate values, functions, and help achieve our targets when used effectively.

## Types of Operators

Python language supports the following types of operators.

• Arithmetic
• Assignment
• Bitwise
• Comparison (Relational)
• Identity
• Logical
• Membership

Now, we shall look at each arithmetic operator with examples, so that it will be a lot easier for one to understand, how does Python, and their operators, really work!

## Python Arithmetic Operators

Let’s assume we have two variable, a =5 and b = 10. Thus:

## Python Comparison Operators

These operators compare the values on either sides of them and decide the relation among them. They are also called Relational operators.

Let’s assume we have two variable, a =5 and b = 10. Thus:

## Python Assignment Operators

Let’s assume we have two variable, a =5 and b = 10. Thus:

## Python Bitwise Operators

Bitwise operator works on bits and performs bit by bit operation. Assume if a = 60; and b = 13; Now in binary format they will be as follows −

a = 0011 1100

b = 0000 1101

—————–

a&b = 0000 1100

a|b = 0011 1101

a^b = 0011 0001

~a  = 1100 0011

There are following Bitwise operators supported by Python language

## Python Logical Operators

There are following logical operators supported by Python language. Let’s assume we have two variable, a =5 and b = 10. Thus:

## Python Membership Operators

Python’s membership operators test for membership in a sequence, such as strings, lists, or tuples. There are two membership operators as explained below:

## Python Identity Operators

Identity operators compare the memory locations of two objects. There are two Identity operators explained below −

## Python Operators Precedence

The following table lists all operators from highest precedence to lowest.

In case, you have any questions, feel free to mention your questions as comments to this specific post. I will try and answer at the earliest.

## Python: Variables

The word variable in itself speaks dynamism. It’s value, quantity, and essence, can change from time to time. In programming as well, your value changes from time to time.

In Python, variables are used to store data, like string, numbers, date-time etc. When you create a variable, a little portion is reserved within your computer memory to store this value of the variable. The value of a variable has to be assigned by you.

## Types of variables

Python has five standard data types:

• Numbers
• String
• List
• Tuple
• Dictionary

## Creating a variable

In Python, a variable does not need to be declared while creating or before adding a value to it. Python variables are usually dynamically typed, that is, the type of the variable is interpreted during run-time and you don’t need to specify the type of a variable.

The following program shows how to use string and integer type variables:

Example

x = 10 # Integer variable
y = “Hello World” # String variable
# Displaying variables value
print(x)
print(y)

Output

10
Hello World

## Checking the type of a variable

With the method type(), we can know the type of variable we have created. It could be int, str, is used to get the type of a created variable.

Example

var1 = ‘Hello World’
print(type(var1))

Output

<class ‘str’>

Important Rules for Variables

• Variables cannot start with a number, but can be Alpha-Numeric. Additionally, they also support underscores – hence the total range is from A-Z, a-z, 0-9, and _.
• Variables are strictly case-sensitive, thus You and you are different variables

## Data Type Conversion

Sometimes, due to functional reasons, we need to convert variables. For this purpose, python is quite straight forward. To convert between types, you simply use the type name as a function. A common industry jargon is ‘Type Casting‘.

There are several built-in functions to perform conversion from one data type to another. These functions return a new object, with the changed data type 🙂.

## An introduction to Python

You have no idea how long I have waited to have my own portal in order to share information, with one, and all. With a lot of patience, time, and effort, I’d like to begin my journey of being an open book, solving some of your problems, and in that process also learning a lot more from you.

To begin with, I would like to introduce Python to you as a concept I like to call SEQLSimple Elegant Quick Learn. So instead of SQL, we have SEQL.

Python is a popular programming language. It was created by Guido van Rossum, and released in 1991, and has a wide array of uses, particularly:

• Web Development
• Software Development,
• Scripting
• Machine Learning
• Artificial Intelligence

Owing to it’s Simple syntax, and an Elegant programming structure, it is Quick to execute and Learn. Over the course of my forthcoming posts, you shall come across a wide range of tutorials, quick solutions, tips, and tricks, that I have documented, learned, and experienced over time.

With my trivial, yet foundational, exposure to Python, I want to document my understanding of programming, and make it as easy for you to grasp the fundamental concepts of programming.

In case you have any doubts, feel free to write down your questions in the comments below. I will try and respond to each one of them.

Before I leave, one has to cut the ribbon by a simple saying….wait for it….”Hello World”.

So how does one do that ? Well, you just type:

print(“Hello, World!”)