Variables, Constants and Operators

Variables

A variable is a location in memory that holds one or more values. It has a label or name to identify it and its values can be changed as the program runs.

It is good practice in programming to give variables a sensible name that will help explain its purpose. What you should not do is put spaces into a name even if the language allows it, as it can be confusing and it is too easy to mistype it later

When name variable good practice is to  add a  underscore to separate the words in the name. For example

first_name = "Laura"  
second_name = "Bradshaw" 

Constants

A constant is a location in memory that holds a value. It has a label or name to identify it and its value cannot be changed as the program runs. A constant is often declared in capital letters to highlight the fact that it is not a variable.

Constant CHRISTMAS_DAY = "25th December"   

Operators

Assignement Operators

Assignment operators assign values.

The simplest assignment operator is “=”. It copies the value of its right argument into the argument on its left.

MyVariable = 2

This assigns the value 2 to the variable named ‘MyVariable’.

The assignment operator can also copy a value from one variable to another. For example

MyVariable = AnotherVariable

Arithmetic Operators

You are already familiar with many simple arithmetic operations: addition, subtraction, division and multiplication. The symbols used to represent these operations in a program are mostly the same ones you see in a maths textbook:-

+ for addition

– for subtraction

* for multiplication

/ for division

Boolean Operators

boolean operator carries out a logical operation on its arguments.

Examples of boolean operators include:

Boolean operators return True or False.