Text Files

Understanding Text Files

Text files are fundamental to data storage and manipulation in Python. They store data as sequences of characters and are human-readable.

Opening and Closing Text Files

To work with text files, you typically use the open() function to open a file and the close() method to close it. However, the preferred method is to use the with statement, which automatically closes the file when the block ends:

Python

with open("my_file.txt", "r") as file:

  # Read or process the file content here

File Modes

The open() function takes a mode argument to specify how you want to interact with the file:

·         r: Read mode (default)

·         w: Write mode (creates a new file or overwrites an existing one)

·         a: Append mode (adds to the end of an existing file or creates a new one)

·         x: Create mode (creates a new file, fails if the file already exists)

·         r+: Read and write mode

·         t: Text mode (default)

·         b: Binary mode (for non-text files)

Reading from Text Files

·         read(): Reads the entire contents of the file as a string.

·         readline(): Reads a single line from the file.

·         readlines(): Reads all lines of the file and returns them as a list of strings.

Python

with open("my_file.txt", "r") as file:

  content = file.read()

  print(content)

Writing to Text Files

·         write(): Writes a string to the file.

·         writelines(): Writes a list of strings to the file.

Python

with open("my_file.txt", "w") as file:

  file.write("This is some text.")

Key Points

·         Always close files after use to release system resources.

·         The with statement is preferred for handling files as it ensures proper closing.

·         Be aware of file modes to perform the desired operations.

·         For large files, consider reading in chunks to optimize memory usage.

·         Handle potential exceptions (e.g., file not found) using try-except blocks.

Additional Considerations

·         Encoding: Specify the encoding when opening the file if necessary (e.g., open("file.txt", "r", encoding="utf-8")).

·         File permissions: Ensure you have the necessary permissions to read or write to a file.

·         File paths: Use absolute or relative paths to specify the file location.

By understanding these concepts and best practices, you can effectively work with text files in your Python programs.