Open()

The open() function in Python is used to open a file and return a corresponding file object. This function is used for reading, writing, and appending data to files. The syntax is open(file, mode), where file is the name (and path) of the file and mode specifies the mode in which the file is opened.

# Open a file in read mode
file = open("example.txt", "r")

# Read the entire content of the file
content = file.read()
print(content)

# Close the file
file.close()

Writing to a File

In Python, you can write to a file using the write() method.

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

# Write some content to the file
file.write("Hello, world!")

# Close the file
file.close()

Appending to a File

In Python, you can append to a file using the write() method with the a mode.

# Open a file in append mode
file = open("example.txt", "a")

# Append some content to the file
file.write("\nAppended text.")

# Close the file
file.close()

Reading a File Line by Line

# Open a file in read mode
file = open("example.txt", "r")

# Read and print each line in the file
for line in file:
    print(line.strip())

# Close the file
file.close()

With Statement

The with statement in Python is used to simplify exception handling by encapsulating common preparation and cleanup tasks in so-called context managers. The with statement is used to wrap the execution of a block of code within methods defined by a context manager.

The with statement is commonly used to open files, acquire locks, and more. When the block of code is exited, the context manager's __exit__() method is called to clean up resources.

# Open a file using the with statement
with open("example.txt", "r") as file:
    # Read the entire content of the file
    content = file.read()
    print(content)
# No need to explicitly close the file; it's done automatically

File Modes

'r' - Read mode (default). Opens a file for reading.
'w' - Write mode. Opens a file for writing (creates a new file or truncates an existing file).
'a' - Append mode. Opens a file for appending (creates a new file if it doesn't exist).
'b' - Binary mode. Can be added to other modes (e.g., 'rb', 'wb') for binary files.
't' - Text mode (default). Can be added to other modes (e.g., 'rt', 'wt').

# Open a file in read mode
file = open("example.txt", "r")

# Read the entire content of the file
content = file.read()
print(content)

# Close the file
file.close()