Python Variables and Data Types

In Python, a variable is a space to store data, used to reference or manipulate values. The equal sign = is used to assign a value to a variable. Python allows assigning values of various data types to variables, and the type of a variable is determined automatically.

x = 10             # Integer variable
name = "Alice"    # String variable
is_active = True   # Boolean variable

Characteristics of Variables

1. Assignment and Type

In Python, when a value is assigned to a variable, the type of that variable is determined automatically. A variable can have various data types, and the same variable can also be assigned different types of values.

x = 10          # Integer
x = "Hello"    # Reassigned as a string

2. Type Checking

You can use the type() function to check the data type of a variable. This will let you know the current data type of the variable.

x = 10
print(type(x))  # 

name = "Alice"
print(type(name))  # 

3. Variable Naming Rules

Variable names can consist of letters, numbers, and underscores (_), but cannot start with a number. They are also case-sensitive.

• Variable names must start with an alphabetic character or an underscore. Example: _value, data1
• Variable names cannot contain spaces. If they consist of multiple words, use underscores to separate them. Example: user_name
• Python reserved words (keywords) cannot be used as variable names. Example: for, if, etc.

4. Dynamic Typing

Python is a dynamic typing language, meaning you do not have to explicitly declare the type of a variable. The type of a variable is automatically determined based on the assigned value.

value = 10          # Assigned as an integer
value = "Python"   # Reassigned as a string

5. Assigning Values to Multiple Variables

In Python, you can initialize multiple variables at once. This helps in writing concise code.

a, b, c = 1, 2, 3
print(a, b, c)  # 1 2 3

Additionally, you can assign the same value to multiple variables.

x = y = z = 0
print(x, y, z)  # 0 0 0

6. Converting Variable Data Types

You can change the data type of a variable through type casting. In Python, functions like int(), float(), str() can be used to convert data types.

num_str = "123"
num_int = int(num_str)  # Convert string to integer
print(type(num_int))    # 

Summary

• A variable is a space for storing data, and its data type is automatically determined when a value is assigned.
• You can check the data type of a variable using the type() function.
• Python variables use dynamic typing, allowing different types of values to be assigned to the same variable.
• You can assign values to multiple variables at once or the same value to multiple variables.
• To convert data types, you can use functions like int(), float(), str().

Variables play a very important role in storing and manipulating data. Understand Python’s flexible variable utilization well and apply it to your programs!