What is difference between raw_input() and input() functions in Python?

When working with user input in Python, developers often encounter two functions: input() and raw_input(). Understanding their differences is crucial for writing compatible code across Python versions.

Python input() Function

The input() function reads input from the user and returns it as a string. However, its behavior differs significantly between Python 2.x and Python 3.x versions.

Python 3.x input() Behavior

In Python 3.x, input() always returns a string, regardless of what the user enters ?

num_1 = input("Enter value of num_1: ")
num_2 = input("Enter value of num_2: ")
print("Values are", num_1, num_2)
print("Type of num_1:", type(num_1))
print("Type of num_2:", type(num_2))

Enter value of num_1: 10
Enter value of num_2: 20
Values are 10 20
Type of num_1: <class 'str'>
Type of num_2: <class 'str'>

Python 2.x input() Behavior

In Python 2.x, input() evaluates the input as Python code, which can be dangerous ?

# Python 2.x behavior (dangerous)
num = input("Enter a number: ")  # If user enters 10, type is int
name = input("Enter name: ")     # If user enters hello, causes NameError

Python raw_input() Function

The raw_input() function was available only in Python 2.x and always returned input as a string, making it safer than Python 2.x's input().

Syntax and Usage

# Python 2.x only
var_1 = raw_input("Enter a value: ")
print(var_1)
print(type(var_1))  # Always <type 'str'> in Python 2.x

Key Differences

Migration Between Versions

When migrating from Python 2.x to 3.x, replace raw_input() with input() ?

# Python 2.x equivalent to Python 3.x
# Python 2.x: raw_input("Enter name: ")
# Python 3.x: input("Enter name: ")

name = input("Enter your name: ")
age = input("Enter your age: ")

# Convert to appropriate type if needed
age = int(age)
print(f"Hello {name}, you are {age} years old")

Enter your name: Alice
Enter your age: 25
Hello Alice, you are 25 years old

Best Practices

Always validate and convert input to the required data type ?

try:
    age = int(input("Enter your age: "))
    print(f"Your age is {age}")
except ValueError:
    print("Please enter a valid number")

Enter your age: 25
Your age is 25

Conclusion

Python 3.x's input() function behaves like Python 2.x's raw_input(), always returning strings. Python 2.x's input() was dangerous as it evaluated code. When migrating to Python 3.x, replace raw_input() with input().