In Python programming, we usually work with different types of data, such as numbers, text, and Boolean values. Sometimes, we need to change one data type into another so that our program can perform the required operation correctly. This process is known as type conversion.

What is Type Conversion?

# Python program to implement type conversion
age = "18"
print(int(age) + 2)

20

Why is Type Conversion Needed?

num = "25"
print(int(num) + 10)

35

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

Enter your age: 22
27

marks = 95
print("Your marks are " + str(marks))

Your marks are 95

Types of Type Conversion

# Python program to implement implicit 
# type conversion
num1 = 15
num2 = 2.5
result = num1 + num2
print(result)
print(type(result))

17.5

class 'float'

1. "num1" is an integer.
2. "num2" is a decimal number.
3. Before performing the addition, Python automatically converts the integer into a float.
4. Therefore, the result is also a float.
5. This automatic conversion is called implicit type conversion.

1. Simplifies Programming: Python automatically converts compatible data types when required, so programmers do not need to write extra conversion code.
2. Saves Time: Since the conversion is handled automatically, developers can focus on writing program logic instead of manually converting data types.
3. Improves Code Readability: Automatic conversion keeps the code shorter and cleaner, making it easier to understand and maintain.
4. Reduces Minor Coding Errors: By automatically converting compatible data types, Python helps avoid simple mistakes that may occur during calculations.
5. Makes Numeric Operations Smooth: When integers and floating-point numbers are used together, Python automatically converts the integer into a float, allowing mathematical operations to be performed without interruption.

# Python program to implement explicit
# type conversion
age = "18"
new_age = int(age)
print(new_age)
print(type(new_age))

int(value)

age = "18"
# Changing data type of variable 'age' from string to integer 
new_age = int(age)
print(new_age)
# To print the data type of the result 
print(type(new_age))

18

class 'int'

price= 49.99
print(int(price))

49

float(value)

marks = "92"
new_marks = float(marks)
print(new_marks)
print(type(new_marks))

92.0

class 'float'

str(value)

age = 18
message = "My age is " + str(age)
print(message)

My age is 18

bool(value)

print(bool(1))
print(bool(0))
print(bool(""))
print(bool("Python"))

True

False

False

True

• Non-zero numbers return "True".
• Zero returns "False".
• An empty string returns "False".
• A non-empty string returns "True".

list(value)

text = "Python"
letters = list(text)
print(letters)

['P', 'y', 't', 'h', 'o', 'n']

tuple(value)

numbers = [10, 20, 30]
new_tuple = tuple(numbers)
print(new_tuple)

(10, 20, 30)

set(value)

numbers = [1, 2, 2, 3, 4, 4]
print(set(numbers))

{1, 2, 3, 4}

dict(value)

student = dict(name="Rahul", age=18)
print(student)

{'name': 'Rahul', 'age': 18}

Complete Program Using Type Conversion

# Converting a string to an integer
age = "18"
age = int(age)
# Converting an integer to a float
height = float(170)
# Converting an integer to a string
marks = str(95)
# Converting a number to Boolean
is_pass = bool(1)
# Converting a string into a list
letters = list("Python")
# Converting a list into a tuple
numbers = [10, 20, 30]
numbers_tuple = tuple(numbers)
# Converting a list into a set
values = [1, 2, 2, 3, 4]
unique_values = set(values)
# Creating a dictionary
student = dict(name="Rahul", age=18)
# Displaying all converted values
print(age)
print(height)
print(marks)
print(is_pass)
print(letters)
print(numbers_tuple)
print(unique_values)
print(student)

18

170.0

95

True

['P', 'y', 't', 'h', 'o', 'n']

(10, 20, 30)

{1, 2, 3, 4}

{'name': 'Rahul', 'age': 18}

Explanation:

1. "int()" converts the string "18" into the integer "18", allowing mathematical operations to be performed.
2. "float()" converts the integer "170" into the floating-point value "170.0".
3. "str()" converts the integer "95" into the string "95", making it suitable for displaying with other text.
4. "bool()" converts the number "1" into the Boolean value "True". Similarly, "0" would become "False".
5. "list()" converts the string "Python" into a list of individual characters.
6. "tuple()" converts a list into a tuple, which cannot be modified after creation.
7. "set()" converts a list into a set and automatically removes duplicate values.
8. "dict()" creates a dictionary containing key-value pairs.
9. Finally, the "print()" function displays all the converted values on the screen.

Common Beginner Mistakes

Wrong:

age = "18"

print(age + 5)
 

Correct:
age = int("18")

print(age + 5)

Wrong:

int("Python")
 

Correct:

int("25")

Wrong:

age = input("Enter Age: ")

print(age + 5)
 

Correct:

age = int(input("Enter Age: "))

print(age + 5)

Example:

print(bool(0))

print(bool(""))
 

Output:

False

False

Wrong:

price = 49.99

print(int(price))

Correct:
price = 49.99
print(float(price)

Conclusion

Frequently Asked Questions

Type conversion is the process of converting one data type into another using built-in Python functions or automatic conversion.

Implicit type conversion is performed automatically by Python, whereas explicit type conversion is performed manually by the programmer.

The "int()" function is used to convert a numeric string into an integer.

Type conversion helps different data types work together, prevents errors, and allows mathematical operations and data processing to be performed correctly.

No. Only strings containing valid numeric values can be converted using the "int()" function.

The most commonly used functions are "int()", "float()", "str()", and "bool()" because they are frequently needed while handling user input and performing calculations.