How to take input in Python?

1. Using input() Function

The input() function reads a line of text entered by the user and returns it as a string.

Syntax:

variable = input(prompt)

• prompt: An optional string displayed to the user as a message before input.
• variable: The variable where the input value is stored.

2. Example: Basic Input

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

Explanation:

• The prompt "Enter your name: " is displayed.
• The user types their name and presses Enter.
• The input is stored as a string in the variable name.
• The program prints a greeting using the entered name.

3. Handling Numeric Input

Since input() returns a string, you need to convert the input into the desired data type (e.g., int or float) if you want to handle numbers.

Example: Taking Integer Input

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

• The int() function converts the input string into an integer.

Example: Taking Float Input

height = float(input("Enter your height in meters: "))
print(f"Your height is {height} meters.")

• The float() function converts the input string into a floating-point number.

4. Input Validation

You should validate user input to ensure the program runs without errors if the user enters unexpected data.

Example: Handling Errors with try and except

try:
    age = int(input("Enter your age: "))
    print(f"You are {age} years old.")
except ValueError:
    print("Invalid input! Please enter a number.")

• If the user enters non-numeric data, the program will catch the error and display a friendly message.

5. Taking Multiple Inputs

You can take multiple inputs on the same line or process multiple inputs efficiently.

Example: Multiple Inputs in a Single Line

x, y = input("Enter two numbers separated by space: ").split()
x = int(x)
y = int(y)
print(f"The sum is {x + y}")

• The split() method separates the input string into parts based on spaces by default.

Example: Using List Comprehension

numbers = [int(x) for x in input("Enter numbers separated by space: ").split()]
print(f"The numbers are: {numbers}")

6. Input Without Prompt

If you don’t provide a prompt, the user can still enter data, but the program won’t display any specific message.

Example:

data = input()
print(f"You entered: {data}")

7. Advanced Techniques

• Default Values: Provide default values if the user enters nothing.

data = input("Enter something (or press Enter to skip): ") or "default"
print(f"You entered: {data}")

• Stripping Extra Whitespace: Remove leading/trailing whitespace using .strip().

data = input("Enter something: ").strip()
print(f"You entered: {data}")

Summary

• Use input() to read data from the user.
• Convert the input to other types using int(), float(), etc., when needed.
• Validate user input and handle any unwanted entries.
• Use advanced techniques such as splitting or stripping to make it usable.