Python File Handling: How to Open, Read, and Write to Files

File handling is a crucial concept in terms of Python programming. More specifically, the “open()” function permits you to access, read, write, and update files in several ways.

So, by understanding its syntax modes and the relevant best practice, you will have full control over different file types and can easily perform the required file operations.

In our first blog of this file handling series in Python, we will explore the techniques of opening files in different types of modes.

Before heading toward the method of opening files in Python, let’s understand what a file is, its different types, and the importance of understanding the file types when working with data.

What is a File in Python

In the context of computer programming, a file is referred to as the collection of related information that is stored on the storage device or your computer like a solid-state drive and hard drive.

More specifically, files are utilized for organizing and storing data in a well-defined structure. You can define any type of data in these files, such as images, text, audio, videos, and others.

Different Types of Files in Python

Here, check out the provided types of files.

• Text Files – These types of files comprise plain text data which contains lines of text or characters. Text files are mostly created and edited with the help of word processing software and text editors.
• Binary Files – These files store data in a binary format, which signifies that the relevant information is represented with binary code. You can add images, executables, audio, videos, and other types of data in the binary files.
• Document Files – These files are defined for particular applications and programs and are utilized for storing formatted data, like spreadsheets, documents, presentations, and PDFs.
• Multimedia Files – These files store video and audio data. For instance, MP3 audio files, JPEG image files, and MP4 video files.

Importance of File Types in Python

As a programmer, it is essential for you to know about the different types of files. It assists in determining how the data within the file is structured and how it can be processed further.

Moreover, each file type has its own particular format, which needs appropriate processing and handling technique.

Several file types can have different compatibility requirements based on software and platforms. Therefore, understanding the file types enables programmers to implement the correct tools and techniques for opening, reading, writing, and performing any other manipulation operation within the files.

Understanding File Paths in Python

In Python, a file path is defined as a unique location or address of a file within a file system. It is utilized for identifying the exact file location, permitting the operation to find out and access the file in order to perform different file operations.

What are File Paths in Python?

Here, we have enlisted the types of file paths that are primarily used in Python:

Absolute File Path

This type of file path offers the exact and complete file location from the root directory of the file system. It contains the whole path hierarchy, starting from the root directory and ending with the file’s name.

For Example:

absolute_path = '/Users/username/Documents/file.txt'

According to the given syntax, the “file.txt” is placed in the Document directory, which is the “username” home directory of the user.

Relative File Path

This path defines the file location relative to the present or current working directory. It does not start from the root, however, it provides a path that starts from the parent or current directory.

For Example:

relative_path = 'data/file.csv'

Here, the “file.csv” is placed in the “data” directory, which is located in the same directory in which the Python script will be executed.

How to Open a File in Python

The “open()” is a built-in function in Python that can be invoked for opening files for reading, writing, and updating data. It creates a connection between the Python script and the file on the underlying file system.

You can use the open() function for reading data from files, accessing files, appending data to the existing files, renaming, moving files, or integrating with external systems through file exchange. It also handles different file types such as binary and text files.

Syntax of open() function

To use the “open()” function in your program, follow the stated syntax.

file_object = open(file_path, mode, buffering)

Here:

• The “file_path” refers to the path of the file that needs to be opened. This file path can be relative or absolute.
• The “mode” is a string value that represents the file mode for opening it.
• The “buffering” is an optional parameter that defines the file buffering policy. By default, its value is set to “-1” for using the default system buffering.

Different Modes to Open a File in Python

There exist different types of file opening modes that you can specify according to your program requirements.

Now, let’s define and explore each of the given file modes with examples.

1. Read Mode

The “r” or read mode is added in the open() function for reading the file. Using this mode you can read the file content but are restricted to writing or modifying the new data to it.

For example, the given Python script will open the “GeeksVeda.txt” file in the read mode using the open() function.

file_path = 'GeeksVeda.txt'
file_object = open(file_path, 'r')

2. Write Mode

The “w” or Write mode opens the file for the purpose of writing. If the file exists on the specified path then the previously written content is over-written. Otherwise, a new file will be created. This mode also permits you to write new data to the file.

Here, we will open the “GeeksVeda.txt” file in the write mode.

file_path = 'GeeksVeda.txt'
file_object = open(file_path, 'w')

3. Append Mode

In the given code, we will “GeeksVeda.txt” file in the append mode by utilizing the open() function.

file_path = 'GeeksVeda.txt'
file_object = open(file_path, 'a')

4. Exclusive Creation Mode

Here, the “GeeksVeda.txt” file will be opened in the Exclusive Creation mode.

file_path = 'GeeksVeda.txt'
file_object = open(file_path, 'x')

5. Binary Mode

This mode can be used for binary files like audio, video files, or simple images.

In this scenario, we have invoked the open() function and added binary mode for opening the “GeeksVeda.jpg” file.

file_path = 'GeeksVeda.jpg'
file_object = open(file_path, 'rb')

6. Buffering Mode

Here, we will open the “GeeksVeda.txt” in the buffering mode with a 4096 buffer size.

file_path = 'GeeksVeda.txt'
file_object = open(file_path, 'r', buffering=4096)

7. Encoding Mode

This mode makes sure the proper decoding or encoding of the text data. In our case, we will now open the “GeeksVeda.txt” file in the encoding mode.

file_path = 'GeeksVeda.txt'
file_object = open(file_path, 'r', encoding='utf-8')

8. Read and Write Mode

This mode allows you to read the existing content of the specified file, update it, and add new data as well.

file_path = 'GeeksVeda.txt'
file_object = open(file_path, 'r+')

9. Text Mode

For instance, now the open() function will open the “GeeksVeda.txt” file in the text mode for reading with “utf-8” encoding.

file_path = 'GeeksVeda.txt'
file_object = open(file_path, 'rt', encoding='utf-8')

10. Updating Mode

Here, we will open the “GeeksVeda.txt” file for both reading and writing.

file_path = 'GeeksVeda.txt'
file_object = open(file_path, 'r+')

Best Practices to Open a File in Python

Have a look at the enlisted best practices for opening files in Python.

• Check the file’s existence before opening using suitable functions.
• Define the file mode to avoid unintended consequences.
• Specify the file encoding while working with text files.
• Utilize the file context managers for simple file handling.
• Validate user input for file operations.
• Clearly define whether you are using a relative or absolute file path.
• Make sure that program has the required permission for accessing the file.

That’s all crucial information regarding opening a file in Python.

Conclusion

Understanding the usage of the “open()” function in Python is essential for handling the file efficiently. By utilizing suitable modes and following the best practices, you can easily read, write, and manipulate files effectively.

In the next article of this series, we will check out the method for reading a file in Python.

You can also check out our dedicated Python Tutorial series!