File I/O

File I/O refers to the process of reading from and writing to files on your computer. Python provides built-in functions and methods that allow us to work with files easily. Here are some examples:

Reading from a File:

To read from a file, you can use the open() function to open the file in read mode ("r"), and then use the read() method to read the contents of the file. Here's an example:

file = open("example.txt", "r")
content = file.read()
print(content)
file.close()

In this code, we open the file named "example.txt" in read mode and assign it to the file variable. We then use the read() method to read the contents of the file and store it in the content variable. Finally, we print the content and close the file using the close() method.

Writing to a File:

To write to a file, you can use the open() function to open the file in write mode ("w"), and then use the write() method to write content to the file. Here's an example:

file = open("example.txt", "w")
file.write("Hello, world!")
file.close()

In this code, we open the file named "example.txt" in write mode and assign it to the file variable. We then use the write() method to write the string "Hello, world!" to the file. Finally, we close the file using the close() method.

Appending to a File:

To append content to an existing file, you can use the open() function to open the file in append mode ("a"), and then use the write() method to append content to the file. Here's an example:

file = open("example.txt", "a")
file.write("\nThis is a new line.")
file.close()

In this code, we open the file named "example.txt" in append mode and assign it to the file variable. We then use the write() method to append the string "\nThis is a new line." to the file. The "\n" is a special character that represents a new line. Finally, we close the file using the close() method.

It's important to note that when working with files, it's a good practice to close the file after you're done using it. Alternatively, you can use the with statement, which automatically closes the file for you. Here's an example:

with open("example.txt", "r") as file:
    content = file.read()
    print(content)

In this code, the with statement opens the file, reads its content, and automatically closes the file when the block of code is finished.

These are some basic examples of file I/O in Python. There are many more operations and methods available for working with files, such as reading line by line, handling errors, and working with different file formats.