Page 455 - ComputerScience_Class_11

iNtroductioN to PytHoN

data ProceSSiNg iN PytHoN

Learning Objectives

12.1 Accepting User Input with input()
12.2 Displaying Output with print()
12.3 Understanding Errors in Python

A program isn't useful if it works alone. To create interactive and dynamic applications, a program needs to communicate
with the outside world. This process is called Input/Output or I/O. The simplest way to achieve this is through the
console (also known as the terminal or command line).
Console I/O involves two main actions:

• Input: Accepting data from the user via the keyboard.
• Output: Displaying text, results or prompts to the user on the screen.
This text-based interface, known as a Command Line Interface (CLI), is a powerful tool for building applications, from
simple scripts to complex software. In this chapter, we will focus on two essential functions for console I/O in Python:
input() and print().

12.1 ACCEPTING USER INPUT WITH INPUT()
The primary way to get data from the user into your Python program is through the built-in input() function. When
this function is called, the program pauses its execution and waits for the user to type something on the keyboard. The
user's input is then passed back to your program.

12.1.1 Using input() for Strings
The input() function can accept an optional string argument, known as a prompt. It helps the user understand
what type of information they should enter. By default, any value entered by the user using the input() function is of
string data type.
The syntax for the input() function is:

variable = input(prompt)
Variable: The variable stores the value entered by the user.

Data Processing in Python 453