How to work with files in Python?

Working with files in Python is straightforward and involves using built-in functions to read from and write to files. The primary function for handling files is the `open()` function, which allows you to open a file in various modes such as reading (`'r'`), writing (`'w'`), appending (`'a'`), and more. ### Reading Files To read a file, you open it in read mode (`'r'`) and then use methods like `.read()`, `.readline()`, or `.readlines()`: ```python with open('example.txt', 'r') as file: content = file.read() # Reads the entire file content as a string print(content) ``` Using the `with` statement is recommended because it automatically handles closing the file, even if an error occurs. If you want to read the file line by line, you can do: ```python with open('example.txt', 'r') as file: for line in file: print(line.strip()) # strip() removes trailing newline characters ``` ### Writing Files To write to a file, open it in write mode (`'w'`). This will create the file if it doesn’t exist or overwrite it if it does: ```python with open('output.txt', 'w') as file: file.write("Hello, World!\n") file.write("This is a new line.") ``` If you want to add content to the end of an existing file without overwriting it, open the file in append mode (`'a'`): ```python with open('output.txt', 'a') as file: file.write("\nThis line is appended.") ``` ### Summary - Use `open(filename, mode)` to open files. - Modes include `'r'` for reading, `'w'` for writing (overwrite), and `'a'` for appending. - Use `with` to automatically manage file closing. - Use `.read()`, `.readline()`, `.readlines()` for reading content. - Use `.write()` to write strings to files. This approach lets you efficiently read and write files in Python, handling most common file operations safely and cleanly.

Working with files in Python is straightforward and involves using built-in functions to open, read, write, and close files. Python provides a simple and consistent way to handle files through the `open()` function, which returns a file object that you can use to perform various file operations. ### Opening a File To work with a file, you first open it using: ```python file = open('filename.txt', mode) ``` The `mode` defines what you want to do with the file: - `'r'` – Read (default mode) - `'w'` – Write (creates a new file or truncates an existing one) - `'a'` – Append (write data at the end of the file) - `'b'` – Binary mode (used with other modes for binary files) - `'+'` – Read and write For example: ```python file = open('example.txt', 'r') # Open for reading ``` ### Reading from a File You can read the entire content with: ```python content = file.read() ``` Or read line by line using: ```python for line in file: print(line) ``` Other useful methods are: - `readline()` – reads one line at a time - `readlines()` – reads all lines into a list ### Writing to a File To write data, open the file in `'w'` or `'a'` mode: ```python file = open('example.txt', 'w') file.write("Hello, world!\n") file.write("Another line.") ``` ### Closing a File Always close the file when done to free system resources: ```python file.close() ``` ### Using `with` Statement (Recommended) A better practice is to use the `with` statement which automatically closes the file, even if exceptions occur: ```python with open('example.txt', 'r') as file: content = file.read() print(content) ``` Similarly, for writing: ```python with open('example.txt', 'w') as file: file.write("Writing with the 'with' statement.") ``` ### Summary - Use `open()` with the appropriate mode. - Use `read()`, `readline()`, or `readlines()` for reading files. - Use `write()` or `writelines()` for writing. - Prefer the `with` statement to handle files safely and cleanly. This approach works for text files. For binary files (like images), open the file in binary mode by adding `'b'` to the mode (e.g., `'rb'` or `'wb'`).