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Variable Naming Convention:
Each language has its own set of rules to declare and initialise a variable. Python also has a
set of conventions to follow when naming a variable:

1. A variable name can include letters, digits, and underscores.
2. A variable name should be user-friendly.

3. Variable names are case-sensitive.

4. A variable name cannot start with a digit.
5. A variable name cannot contain space characters.

Let’s take some examples and understand valid and invalid variable names:
Name, first.name, 2ndName, amount in $

In the above examples, only Name is a valid identifier or variable name.
Read the conventions and try to identify the reason for the invalid variable names.

Variable names are case-sensitive, which means names written in lowercase and uppercase
are treated as two different variables — like Age and age, which are two different variables.

Assigning Values to a Variable:
To assign a value to a variable, an equal sign (=) is used.

Age = 23

Here, Age is a variable with the value 23.

2.4.3 Data type
Now, how much memory a variable occupies depends on the type of data it is assigned.

Therefore, data types determine the amount of memory required to store the variable.
Python supports five standard data types:

1. Number: The data types that store numeric values are called Python numbers. Python
has three kinds of numeric values: integer, float, and complex.

Example:

X = 89 # X is an integer variable
Y = 89.6 # Y is a float variable

Z = 23j # Z is a complex variable

2. String: A string is a sequence of characters. These sets of characters are represented
using either single quotes (‘ ‘) or double quotes (“ “).
Example:

Name = “Akbar”
# or
Name = ‘Akbar’

24 KVS DELHI REGION 2025