File Handling

File handling is a crucial part of computer programming and is used in every language. It is a way to store data, retrieve data, and manipulate data. In this article, we will discuss how file handling works with Python and how to use it to store, retrieve, and manipulate data. We’ll use examples so that you can understand the concepts better and apply them to your own programs.

What is Input and Output?

Input and Output, commonly referred to as I/O, is the process of providing input to a program and receiving output from a program. Input is any type of data that is provided to a program, such as text, numbers, or files. Output is the result of a program’s computation, such as text, numbers, or files. I/O is a fundamental concept in programming and data structures and algorithms, as it allows programs to interact with the user and receive data as input and provide results as output.

I/O in Python

Python provides several built-in functions for performing I/O. The most commonly used functions are print, input, and open. These functions are used to print output to the screen, receive input from the user, and open files, respectively. Let’s take a look at each of these functions in more detail.

print

The print function is used to print output to the screen. It takes a single argument, which is the value to be printed. The argument can be any type of data, such as a string, number, or list.

For example, the following code prints “Hello World!” to the screen:

print("Hello World!")

input

The input function is used to receive input from the user. It takes a single argument, which is the prompt for the user’s input. The prompt is usually a string, but it can also be a number or a list.

For example, the following code prompts the user to enter their name and stores the input in the variable name:

name = input("Please enter your name: ")

What is File Handling?

File handling is the process of reading and writing data from and to files stored on a computer or other storage device. The data can be anything from text, to images, to programs, to binary files, and more. It’s important to understand how to use file handling as it allows you to store important data and make sure it persists even after your program ends.

File handling allows you to perform a variety of operations on files, such as reading and writing data, copying files, deleting files, and more. It’s also important to understand the different types of files and how they are used. By understanding these concepts, you will be able to create more efficient programs that can handle different types of data.

File Handling in Python

Python is a popular programming language that has a variety of built-in functions and modules to help you work with files. In Python, there are two main modules used for file handling: the os module and the shutil module. The os module provides functions to interact with the operating system while the shutil module provides functions to interact with files. With these modules, you can create, open, read, write, and delete files.

Creating Files in Python

To create a file in Python, you can use the open() function. This function takes two arguments: the name of the file and the mode of the file. The mode of the file can be ‘r’ for read-only, ‘w’ for write-only, ‘a’ for append-only, or ‘x’ for create-and-write.

For example, to create a file called ‘test.txt’ in write-only mode, you would use the following code:

file = open('test.txt', 'w')

The open() function will return a file object. You can then use the write() method to write data to the file.

Writing Files in Python

Once you have created a file, you can then write data to it. You can write data either as a string or as a list. To write data as a string, you can use the write() method. For example, to write ‘Hello World’ to a file called ‘test.txt’, you would use the following code:

file = open('test.txt', 'w')
file.write('Hello World')
file.close()

To write data as a list, you can use the writelines() method. For example, to write a list of strings to a file called ‘test.txt’, you would use the following code:

file = open('test.txt', 'w')
list_of_strings = ['Hello', 'World']
file.writelines(list_of_strings)
file.close()

Reading Files in Python

Once you have written data to a file, you can then read the data. To read data from a file, you can use the read() or readlines() method. The read() method will read the entire file and return a string, while the readlines() method will read each line of the file and return a list of strings.

For example, to read the file ‘test.txt’ and store the data in a variable called ‘data’, you would use the following code:

file = open('test.txt', 'r')
data = file.read()
file.close()

Copying Files in Python

You can also use the shutil module to copy files in Python. The shutil module provides a copy() function which takes two arguments: the source file and the destination file. For example, to copy the file ‘test.txt’ to the file ‘test_copy.txt’, you would use the following code:

import shutil
shutil.copy('test.txt', 'test_copy.txt')

Deleting Files in Python

Finally, you can use the os module to delete files. The os module provides a remove() function which takes one argument: the file to be deleted. For example, to delete the file ‘test.txt’, you would use the following code:

import os
os.remove('test.txt')

Conclusion

In this article, we discussed how to use file handling in Python. We covered how to create, open, read, write, and delete files, as well as how to copy files. We also discussed the different types of files and what the different modes of a file mean. With this knowledge, you should now be able to create programs that can store and manipulate data effectively.

Exercises

file = open('data.txt', 'w')
list_of_strings = ['Hello World', 'This is a test', 'File handling is cool!']
file.writelines(list_of_strings)
file.close()

file = open('data.txt', 'r')
data = file.readlines()
for line in data:
    print(line)
file.close()

import shutil
shutil.copy('data.txt', 'data_copy.txt')

file = open('data.txt', 'a')
file.write('This is an additional line')
file.close()

import os
os.remove('data_copy.txt')