Writing Files to txt in Python

When writing Python applications, you often need to save program output or processing results to a file. This article will explain how to write files to txt files in Python.

Opening and Closing Files

Before writing to a file, we need to open it using Python’s built-in open function. The open function accepts two parameters: the file path and the file mode. File modes include read (r), write (w), and append (a).

• ‘r’: Read
• ‘w’: Write
• ‘a’: Append

Here is a brief introduction to write modes. When opening a file in write mode, if the file already exists, its contents will be overwritten; if the file does not exist, a new file will be created. The example code is as follows:

# Open a file and write to it in w mode
file = open("example.txt", "w")

# Write to the file
file.write("Hello, World!")

# Close the file
file.close()

Note that after completing file operations, we must close the file using the close method to release the file handle. Forgetting to close the file may result in resource leaks or file inaccessibility.

In addition to manually closing a file using the close method, we can also use the with statement to automatically close a file. The example code is as follows:

# Use the with statement to automatically close a file
with open("example.txt", "w") as file:
file.write("Hello, World!")

When the with statement block completes, Python automatically calls the file object’s close method to close the file.

File Writing Process

Once the file is opened and in write mode, we can use the write method to write data to the file. The write method accepts a string argument representing the content to be written.

The example code is as follows:

with open("example.txt", "w") as file:
file.write("This is the first line.n")
file.write("This is the second line.n")
file.write("This is the third line.")

In the above example, we write three lines to the file. Note that we add a newline character “n” at the end of each line to make each line a separate line. Without the newline character, all content is written on one line.

Example Code

The following is a complete example code that includes the file opening, writing, and closing operations.

# Open a file and write its contents in w mode
with open("example.txt", "w") as file:
# Write the contents to the file
file.write("This is the first line.n")
file.write("This is the second line.n")
file.write("This is the third line.")

# Open a file and read its contents in r mode
with open("example.txt", "r") as file:
# Read all the contents
content = file.read()

# Print the read contents
print(content)

Conclusion

This article introduced how to write to a txt file in Python, including file opening, writing, and closing operations. Mastering file writing techniques is crucial when writing Python applications. I hope this article is helpful.