Append Text or Lines to a File in Python

Appending text or lines to a file is a common operation in programming, especially when you want to add new information to an existing file without overwriting its content. In Python, this task is made simple with built-in functions that allow you to open a file and append data to it. In this tutorial, we’ll explore what it means to append text or lines to a file and provide examples of both operations in Python.

What is Append Text or Lines to a File?

Appending text or lines to a file involves adding new content to the end of an existing file. It is a useful operation when you want to update or extend the information in a file without losing the existing data. Python provides the open() function to open a file and the write() method to add text, and the write() or writelines() methods to append lines to a file.

How To Append Text Or Lines To A File In Python?

Below, are the example of How To Append Text Or Lines To A File In Python.

Append Text to a File

In this example, the Python function `append_text_to_file` appends the given `text_to_append` to the specified `file_path`. It opens the file in ‘a’ (append) mode, writes the text followed by a newline, and prints a success message. If any error occurs during the process, it prints an error message. The example usage demonstrates appending the specified text to the file ‘example.txt’.

Python3

def append_text_to_file(file_path, text_to_append):
    try:
        with open(file_path, 'a') as file:
            file.write(text_to_append + '\n')
        print(f"Text appended to {file_path} successfully.")
    except Exception as e:
        print(f"Error: {e}")

# Example Usage
file_path = 'example.txt'
text_to_append = 'This is a new line of text.'
append_text_to_file(file_path, text_to_append)

Output

Text appended to test.txt successfully.

.txt File

This is a new line of text.

Append Lines to a File

In this example, Python function `append_lines_to_file` appends the given list of `lines_to_append` to the specified `file_path`. It opens the file in ‘a’ (append) mode, joins the lines with newline characters, writes them to the file, and prints a success message. If any error occurs during the process, it prints an error message.

Python3

def append_lines_to_file(file_path, lines_to_append):
    try:
        with open(file_path, 'a') as file:
            file.write('\n'.join(lines_to_append) + '\n')
        print(f"Lines appended to {file_path} successfully.")
    except Exception as e:
        print(f"Error: {e}")

# Example Usage
file_path = 'example.txt'
lines_to_append = ['Geek 1', 'Geek 2', 'Geek 3']
append_lines_to_file(file_path, lines_to_append)

Output

Lines appended to example.txt successfully.

.txt File

Geeks 1
Geek 2
Geek 3

Conclusion

Appending text or lines to a file in Python is a straightforward process using the the with the ‘a’ (append) mode. This allows you to update files without losing existing data, making it a valuable technique for various programming tasks. Always handle file existence appropriately, and be cautious about potential exceptions during file operations.