File Handling
File Handling
Introduction
- File handling is the process of creating, reading, writing, and closing files using programming.
- In programming, a file is a container in a computer system where data is stored.
Opening Files
- Before a file can be read or written to, it must be opened using a file handling command in the programming language you’re using.
- This command will return a file handle, which is like a cursor that you can control to read or write data at different positions in the file.
- Files can be opened in different modes, including ‘read’ (
r
), ‘write’ (w
), ‘append’ (a
), and others.
Reading Data
- Reading data from a file is called file input.
- This involves opening the file in ‘read’ mode, then using a function or command to read data from the file.
- Reading can happen in many ways - for example, you might read the entire file at once, or you might read the file a line at a time.
Writing Data
- Writing data to a file is called file output.
- This involves opening the file in ‘write’ or ‘append’ mode, and then using a function or command to write data to the file.
- Be aware that opening a file in ‘write’ mode will erase any existing data in the file.
- ‘Append’ mode will allow you to add data to the end of the file without erasing existing data.
Closing Files
- Once you are finished with a file, it’s important to close it.
- Closing a file makes sure that any changes you made are saved and that system resources are freed up.
- Not closing a file can result in data loss or data corruption.
File Paths
- Files are located on your computer’s file system by their File Path.
- This path starts at a root directory and specifies every folder and subfolder until it reaches the file.
- File paths can be absolute, meaning they start from the root of the file system, or relative, meaning they start from the current directory.
Error Handling
- File handling often involves error handling, as many things can go wrong, such as a file not existing, a file not opening correctly, a read or write operation failing, and more.
- Errors can be handled with try…except blocks in Python and similar constructs in other languages.
- Handling errors gracefully can make your program more robust and user-friendly.