File I/O and Exception Handling in python

 File I/O is the process of reading and writing data to and from files on disk. In Python, you can use the built-in open function to open a file and access its contents.

Here's an example of how to read the contents of a file:

python
with open("filename.txt", "r") as file:
    contents = file.read()
    print(contents)

In this example, we use the with statement to open the file in read mode ("r") and assign it to the variable file. The with statement automatically closes the file when we're done with it. We then use the read method of the file object to read the entire contents of the file into the variable contents.

Here's an example of how to write data to a file:

python
with open("filename.txt", "w") as file:
    file.write("Hello, world!")

In this example, we open the file in write mode ("w") and assign it to the variable file. We then use the write method of the file object to write the string "Hello, world!" to the file.

Exception Handling

Exception handling is the process of handling errors and exceptions in your code. In Python, you can use the try and except statements to catch and handle exceptions.

Here's an example of how to catch an exception:

python
try:
    x = 1 / 0
except ZeroDivisionError:
    print("Cannot divide by zero.")

In this example, we use the try statement to attempt to divide the number 1 by 0, which would normally result in a ZeroDivisionError. We use the except statement to catch the exception and print an error message.

You can also use the finally statement to execute some code after the try and except statements, regardless of whether an exception was raised or not:

python
try:
    x = 1 / 0
except ZeroDivisionError:
    print("Cannot divide by zero.")
finally:
    print("This will always be executed.")

In this example, the finally statement is used to print a message after the try and except statements have executed, regardless of whether an exception was raised or not.