Python Write Text File

Summary: in this tutorial, you’ll learn various ways to write text files in Python.

TL;DR #

The following illustrates how to write a string to a text file:

with open('readme.txt', 'w') as f:
    f.write('readme')Code language: JavaScript (javascript)

Steps for writing to text files #

To write to a text file in Python, you follow these steps:

• First, open the text file for writing (or append) using the open() function.
• Second, write to the text file using the write() or writelines() method.
• Third, close the file using the close() method.

The following shows the basic syntax of the open() function:

f = open(file, mode)

The open() function accepts many parameters. But you’ll focus on the first two:

• The file parameter specifies the path to the text file that you want to open for writing.
• The mode parameter specifies the mode for which you want to open the text file.

For writing to a text file, you use one of the following modes:

The open() function returns a file object that has two useful methods for writing text to the file: write() and writelines().

• The write() method writes a string to a text file.
• The writelines() method write a list of strings to a file at once.

The writelines() method accepts an iterable object, not just a list, so you can pass a tuple of strings, a set of strings, etc., to the writelines() method.

To write a line to a text file, you need to manually add a new line character:

f.write('\n')
f.writelines('\n')Code language: JavaScript (javascript)

Writing text file examples #

The following example shows how to use the write() function to write a list of texts to a text file:

lines = ['Readme', 'How to write text files in Python']
with open('readme.txt', 'w') as f:
    for line in lines:
        f.write(line)
        f.write('\n')Code language: JavaScript (javascript)

If the readme.txt file doesn’t exist, the open() function will create a new file.

The following shows how to write a list of text strings to a text file:

lines = ['Readme', 'How to write text files in Python']
with open('readme.txt', 'w') as f:
    f.writelines(lines)Code language: JavaScript (javascript)

If you treat each element of the list as a line, you need to concatenate it with the newline character like this:

lines = ['Readme', 'How to write text files in Python']
with open('readme.txt', 'w') as f:
    f.write('\n'.join(lines))Code language: JavaScript (javascript)

Appending text files #

To append to a text file, you need to open the text file for appending mode. The following example appends new lines to the readme.txt file:

more_lines = ['', 'Append text files', 'The End']

with open('readme.txt', 'a') as f:
    f.write('\n'.join(more_lines))Code language: JavaScript (javascript)

Output:

Writing to a UTF-8 text file #

If you write UTF-8 characters to a text file using the code from the previous examples, you’ll get an error like this:

UnicodeEncodeError: 'charmap' codec can't encode characters in position 0-44: character maps to <undefined>Code language: HTML, XML (xml)

To open a file and write UTF-8 characters to a file, you need to pass the encoding='utf-8' parameter to the open() function.

The following example shows how to write UTF-8 characters to a text file:

quote = ''

with open('quotes.txt', 'w', encoding='utf-8') as f:
    f.write(quote)
Code language: JavaScript (javascript)

Summary #

• Use the open() function with the w or a mode to open a text file for appending.
• Always close the file after completing writing using the close() method or use the with statement when opening the file.
• Use write() and writelines() methods to write to a text file.
• Pass the encoding='utf-8' to the open() function to write UTF-8 characters into a file.

Quiz #