Fundamentals 3 min read

Master Python Input/Output: From basic input() to custom functions

This tutorial walks through Python’s built-in input() and print() functions, shows how to capture user input, format it with the % operator, and then demonstrates creating and invoking a simple custom function while stressing proper indentation, all illustrated with code snippets and screenshots.

AI Large-Model Wave and Transformation Guide

Nov 16, 2017

Master Python Input/Output: From basic input() to custom functions

In Python every program interacts with the user through built-in functions for input and output. The article first explains that an input prompt such as a = input("name ? ") displays the string “name ? ” in the console, waits for the user to type a line, and then stores the entered text in variable a. A second call b = input("age ? ") works the same way for the age value.

After collecting the two strings, the script builds a formatted message using the old‑style % operator: c = "so you name is %r ,and you are %r " % (a,b). The resulting string is printed with print(c), producing a single line that echoes the user’s name and age.

The tutorial then reminds that print() and input() are predefined functions provided by the Python runtime, which can be called directly without any prior definition. To illustrate how a user-defined function works, the article defines a simple function:

def helloworld():
    print("Executing the defined function")
helloworld()

The author emphasizes the importance of correct indentation in Python, because the language uses whitespace to delimit blocks. When the function helloworld() is invoked, the body executes and the message “Executing the defined function” appears, demonstrating that custom functions behave like built-in ones.

Throughout the piece the author interleaves explanatory text with code snippets and screenshots (shown below) that capture the exact console output and the source file view, reinforcing the step-by-step learning process.