input()

input([prompt])

The input() function reads a single line from standard input (typically the keyboard) and returns it as a string, excluding the trailing newline. If a prompt string is provided, it is displayed to the user before waiting for input. This function is essential for creating interactive command-line programs that communicate with users through the console.

Syntax

input([prompt])

Parameters

Parameter	Type	Default	Description
prompt	str	None	The string printed to standard output before reading input

Examples

Basic usage

name = input()
print(f"Hello, {name}!")

With a prompt

age = input("Enter your age: ")
print(f"You are {age} years old")

Handling EOF

When input reaches end-of-file (Ctrl+D on Unix, Ctrl+Z on Windows), input() raises EOFError:

try:
    data = input()
    print(f"Received: {data}")
except EOFError:
    print("No more input available")

Common Patterns

Converting input to other types

age = int(input("Enter your age: "))
price = float(input("Enter price: "))
is_active = bool(input("Active? (yes/no): ").lower() == "yes")

Reading from a file interactively

while True:
    try:
        command = input(">>> ")
        if command.lower() in ("exit", "quit"):
            break
        print(f"Executing: {command}")
    except EOFError:
        print("\nGoodbye!")
        break

Validating input with a loop

while True:
    response = input("Do you want to continue? (yes/no): ").lower().strip()
    if response in ("yes", "no"):
        break
    print("Please answer yes or no")

Safe numeric input

def get_integer(prompt):
    while True:
        try:
            return int(input(prompt))
        except ValueError:
            print("Please enter a valid integer")

def get_float(prompt):
    while True:
        try:
            return float(input(prompt))
        except ValueError:
            print("Please enter a valid number")

age = get_integer("Enter your age: ")
price = get_float("Enter price: ")

Errors

• EOFError — Raised when input reaches end-of-file without any data
• KeyboardInterrupt — Raised when the user interrupts with Ctrl+C

nThe input() function is synchronous and blocks execution until the user provides input. This behavior is important to understand when building interactive applications. In Python 2, the equivalent function was called raw_input().

See Also

• print()
• open()
• str()