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File Handling in Python (Files I/O)

Written by Rahul Lath

Python Tutorials

1Python Overview2Python Tutorial: A Comprehensive Guide for Beginners3Python Keywords and Identifiers4Download and Installation Guide for Python5Python Syntax (With Examples)6Python Comments7Python Variables (With Examples)8Taking Input in Python9Output in Python10File Handling in Python (Files I/O)11Python Operators (With Examples)12Ternary Operators in Python13Operator Overloading in Python14Division Operators in Python15Input from Console in Python16Output Formatting in Python17Any All in Python18Difference between Python Equality and Identity Operators19Python Membership and Identity Operators20Python Data Types21Python Dictionary22Control Flow in Python23Python Arrays24Looping Techniques in Python25Chaining Comparison Operators in Python26Python Functions27Python Strings28Python Numbers29Python Sets30Python For Loops31Python While Loops32Python Break Statement:33Python Continue Statement34Python pass Statement35Args and Kwargs in Python36Python Generators37Python Lambda38Global and Local Variables in Python39Global Keyword in Python40Python Closures41Python Decorators42Memoization using Decorators in Python43Constructors in Python44Encapsulation in Python45Inheritance in Python46Polymorphism in Python47Class Method vs Static Method in Python48Python Exception Handling49First Class Functions in Python50Python Classes And Objects51Errors and Exceptions in Python52Built-In Exceptions in Python53Append to file in Python54File Handling in Python55Destructors in Python56User-Defined Exceptions in Python57Class or Static Variable in Python58Python Tuples59Reading File in Python60Writing File in Python61Opening and Closing Files in Python62NZEC error in Python63Operator Function64Webscraper Python Beautifulsoup65Python Pyramid Patterns66Python Start Patterns67Web Crawler in Python68Build a Python Youtube Downloader69Currency Convertor in Python70Python Website Blocker
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What is File Handling in Python?

Python is a popular programming language that can be used for a wide range of tasks, such as making web apps and analyzing data. Every computer language needs to handle input and output, and Python is no different. Your Python programs will be more dependable and user-friendly if you handle input and output [(I/O) handing] properly. This guarantees that they can communicate with the user and other systems in an effective manner.

This article will give a full explanation of how Python handles input and output. It will cover topics like basic input and output, reading and writing files, formatting output, and handling errors. You will have a firm understanding of how to handle input and output in your Python applications by the end of this article.

Basic Input and Output in Python

The two most common functions for basic input and output in Python are input() and print(). The input() function is used to prompt the user for input, while the print() function is used to display output to the user.

Here is an example of using the input() function to prompt the user for their name and then using the print() function to display a greeting:

name = input("What is your name? ") print("Hello, " + name + "!")

In this example, the input() function prompts the user for their name, and the value entered is assigned to the variable name. The print() function then displays a greeting message that includes the value of the name variable.

Here is another example of using the print() function to display output:

print("The answer is", 42)

In this example, the print() function displays the text “The answer is” followed by the value 42. The comma between the two arguments separates them and automatically adds a space between them in the output.

You can also use string formatting to create more complex output. Here is an example using the format() method to insert a value into a string:

age = 30 print("I am {} years old".format(age))

In this example, the value of the age variable is inserted into the string using the curly braces {} as a placeholder. The format() method is then called on the string, with the value to be inserted passed as an argument.

These are just a few examples of basic input and output in Python using the input() and print() functions. In the next section, we will explore how to read and write files in Python.

Advanced Input Handling in Python

The input() function in Python has a few additional syntax and parameters that can be used for advanced input handling. The basic syntax of the input() function is as follows:


The prompt parameter is a string that is displayed to the user to prompt them for input.

The input() function can also be used to take different types of input, including numeric and string input, and handle multiple inputs in a single line. Here are a few examples:

# Taking integer input age = int(input("What is your age? ")) # Taking floating-point input temperature = float(input("What is the temperature? ")) # Taking multiple inputs in a single line name, age, city = input("Enter your name, age, and city: ").split(", ")

In the first example, the int() function is used to convert the string input to an integer. In the second example, the float() function is used to convert the string input to a floating-point number. In the third example, the split() method is used to split the input string into multiple values, separated by a comma.

When handling input in Python, it is important to follow best practices, such as input validation and sanitization, meaningful prompts, and proper formatting of input data. Here is an example of validating user input to ensure that the input is a positive integer:

while True: try: age = int(input("Enter your age: ")) if age < 0: raise ValueError("Age must be a positive integer") break except ValueError: print("Invalid input. Please enter a positive integer.")

In this example, the try and except statements are used to catch any errors that may occur when converting the input to an integer. The if statement checks that the input is a positive integer, and if not, a ValueError is raised with an appropriate error message.

Advanced Output Handling in Python

In addition to the basic print() function, Python provides several options for advanced output handling, including output formatting, alignment, and sign specification. The str.format() method is a powerful tool for formatting output in Python. Here are a few examples:

# Formatting output by position print("{0} is a {1}".format("Python", "programming language")) # Formatting output by name print("{language} is a {type}".format(language="Python", type="programming language")) # Output alignment and sign specification print("{:<10} {:>10}".format("Left", "Right")) print("{:+d}".format(42))

In the first example, the 0 and 1 inside the curly braces {} correspond to the first and second arguments of the format() method, respectively. In the second example, the names language and type are used instead of indices to specify the values to be inserted into the string.

The third example shows how to align output to the left and right, and the fourth example shows how to specify a sign for numeric output.

Python also provides control sequences for modifying output and adding color to output. Here is an example of adding color to output:

# Adding color to output print("\033[1;31;40m Red Text \n")

In this example, the control sequence \033[1;31;40m is used to set the text color to red. The sequence can be modified to change the color or other attributes of the text.

Python also provides options for outputting to files using the open() function and different file modes. Here is an example of writing output to a file:

# Writing output to a file with open("output.txt", "w") as f: f.write("Hello, world!")

In this example, the with statement is used to ensure that the file is properly closed after writing. The “w” parameter specifies that the file should be opened in write mode, and the write() method is used to write the output string to the file.

Python also supports reading input from files using the open() function and the read methods read(), readline(), and readlines(). Here is an example of reading input from a file:

# Reading input from a file with open("input.txt", "r") as f: for line in f: print(line.strip())

In this example, the with statement is used to ensure that the file is properly closed after reading. The “r” parameter specifies that the file should be opened in read mode, and the for loop is used to iterate over each line of the file using the readline() method.

In conclusion, proper input and output handling is an essential aspect of programming in Python. Understanding the basic and advanced input and output functions, syntax, and parameters, as well as the best practices and options for input validation, sanitization, formatting, and output control, can help programmers create more efficient and effective Python programs.

Common Mistakes to Avoid

When using Python to handle input and output, programmers should avoid making a few common mistakes. They consist of:

  1. Not verifying input: It’s crucial to validate input to make sure it’s the right kind and falls within the expected range. If you don’t, your software can crash or produce inaccurate results.
  2. Sanitizing input: Input needs to be cleaned up to get rid of any malicious code or characters. Inaction on your part could lead to security flaws.
  3. Not formatting output: Output should be formatted correctly so that it is easy to read and understand.If this isn’t done, users may have trouble interpreting the results.
  4. Not closing files correctly: It’s important to close files correctly after reading from or writing to them to avoid memory leaks or file corruption.
  5. Best practices for managing input and output in Python include validating and sanitizing input, putting output in the right format, and making sure files are closed. 


Python programming requires careful management of input and output. Although the input() and print() functions are the fundamental building blocks of input and output (I/O) handling, Python programs may be made more effective and efficient by using a variety of extra features and choices.

Programmers can design programs that are simpler to use, more secure, and easier to comprehend by understanding the syntax and parameters of the input() and print() methods, as well as best practices for input validation, sanitization, formatting, and output control.


What is handling input?

Handling input is the process of dealing with the input devices such as keyboard, mouse, scanner, microphone, and touch screen to interact with the computer or a program. It involves collecting and processing the data entered through these devices to produce an output. For instance, when a user types on the keyboard, the computer receives the input and processes it to display it on the screen or perform a specific action. Handling input requires knowledge of the input devices and their functionalities, and the ability to manage the input data effectively.

How do you manage input and output operations?

The management of input and output operations involves several strategies to optimize the performance of a computer system. Some of the techniques used to manage input and output operations include buffering, caching, and spooling. Buffering involves temporarily storing input or output data in a buffer memory to enable the system to handle large volumes of data efficiently. Caching involves storing frequently accessed data in a cache memory to reduce the time needed to access the data. Spooling involves storing output data in a queue to allow the system to process other tasks while the data is being printed or displayed.

What is output handling?

Output handling is the process of managing the output devices such as printers, monitors, and speakers to display or produce the output of a program or system. Output handling involves controlling the format and appearance of the output, such as font size, color, and alignment. The process of output handling also involves managing the output queue, which allows the system to process other tasks while waiting for the output to be produced. Effective output handling requires knowledge of the output devices and their functionalities, as well as the ability to manage the output data effectively.

What is input and output system in OS?

The input and output system in OS is responsible for managing the communication between the computer system and the input/output devices. It involves handling the input data from the input devices such as the keyboard, mouse, and touch screen, and managing the output data to the output devices such as the monitor, printer, and speakers. The input and output system in OS includes several components such as device drivers, input/output controllers, and input/output subsystems. These components work together to ensure that the input/output operations are properly managed, and the data is accurately processed, displayed, or stored. Effective management of the input and output system in OS requires knowledge of the hardware and software components of the computer system, as well as the ability to troubleshoot and resolve any input/output issues that may arise.

Written by

Rahul Lath

Reviewed by

Arpit Rankwar

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