Python Type Casting | Python

Type casting in Python is the process of converting one data type into another. It is used when a value needs to be treated as a different type so that an operation can be performed correctly. Casting is especially important when working with user input, calculations, and mixed data types.

Python provides built-in functions to convert values from one type to another.

Why Type Casting Is Needed

In Python, different data types behave differently. You cannot directly perform certain operations between incompatible types. For example, user input is always received as a string, even if the user enters a number.

Problem Without Casting

age = input("Enter your age: ")
print(age + 5)

If the user enters 20, Python tries to add "20" and 5, which causes an error because a string and an integer cannot be added.

Solution Using Casting

age = int(input("Enter your age: "))
print(age + 5)

Now:

input() returns a string
int() converts it into a number
Python can perform the calculation correctly

Common Type Casting Functions

Python provides several built-in casting functions.

int()

Converts a value into an integer.

x = "10"
y = int(x)

print(y + 5)   # Output: 15

float()

Converts a value into a float.

price = "99.5"
new_price = float(price)

print(new_price + 10)  # Output: 109.5

str()

Converts a value into a string.

age = 21
message = "Your age is " + str(age)

print(message)   # Output: Your age is 21

bool()

Converts a value into a Boolean.

print(bool(0))        # False
print(bool(1))        # True
print(bool(""))       # False
print(bool("Python")) # True

Implicit vs Explicit Type Casting

Implicit Casting (Automatic)

Python automatically converts types when it is safe.

x = 10
y = 2.5
result = x + y

print(result)     # 12.5
print(type(result))  # float

Python converts 10 into 10.0 automatically.

Explicit Casting (Manual)

The programmer forces the conversion.

total = "100"
total = int(total)

print(total + 50)   # 150

Real-Life Example (Clear & Practical)

Think about online shopping.

You select 2 items.

The website receives quantity as text: "2".

The price is a number: 500.

Before calculating the total, the system must convert "2" into a number.

quantity = "2"
price = 500

total = int(quantity) * price
print(total)

Without type casting, the calculation is impossible.

Conclusion

Type casting allows Python to work smoothly with different kinds of data. It helps programs handle user input, perform calculations correctly, and avoid errors. Understanding type casting is essential for writing reliable and flexible Python code.