Input

In our previous article, we examined the print function and how it outputs values to the console. In this lesson, we dive into another essential function: the input function. The input function prompts the user to enter data via the console and returns the entered value as a string.

Understanding the Input Function

The input function is designed to pause program execution until the user provides an input. You can include a prompt within the input function to guide the user on what to enter. Consider the following example demonstrating the output of a simple print command:

>>> print("Hello!")
Hello!

Capturing User Input

To capture user input, you assign the result of the input function to a variable. In the snippet below, a prompt is displayed, and the user's response is stored:

>>> input("How are you feeling today? ")
How are you feeling today? Fantastic!

Example: Capturing a Favorite Color

If you want to know a user's favorite color, assign the input to a variable and then use that variable later in your program:

favorite_color = input("What is your favorite color? ")
print("Your favorite color is " + favorite_color)

Working with Numerical Input

When a user enters a number, it is returned as a string. Attempting to perform arithmetic operations on a string will result in a TypeError. Consider this example:

>>> age = input("How old are you? ")
How old are you? 22
>>> print(age - 10)
TypeError: unsupported operand type(s) for -: 'str' and 'int'

To enable arithmetic operations, you need to convert the input string into a numerical type. Python provides typecasting functions such as int() to convert a string to an integer or float() for a floating-point number.

Converting Input Using Typecasting

Here’s how you can convert the user input from a string to an integer before performing subtraction:

age = input("How old are you? ")
print(int(age) - 10)

Alternatively, you can wrap the input function with int() directly to ensure that the returned value is numeric:

age = int(input("How old are you? "))
print(age - 10)

Summary

Let's review what we've learned about the Python input function:

• The input function pauses the program and waits for a user response.
• You can provide a prompt string inside the input function to guide the user.
• The value returned by input() is always a string.
• Use typecasting functions such as int() or float() to convert the input into a numeric type for arithmetic operations.

This concludes our exploration of the input function. Stay tuned for more in-depth Python tutorials in the next lesson!