RE: How to handle exceptions in Python?
While coding, I stumbled upon some exceptions. Could someone guide me how to handle exceptions in Python?
In Python, exceptions can be handled using the try, except, and finally statements.
Here's how it generally looks:
```python
try:
# code in this block where exception might occur
except SomeException:
# code to handle the exception
finally:
# code that will be executed no matter what, exception or not
```
The code in the `try` block is the action that you want to monitor for exceptions. The code in the `except` block is what will be executed if an exception of the specified type is raised in the try block.
Let's demonstrate a simple example:
```python
try:
x = int('five')
except ValueError:
print("That's not a valid number!")
```
In the above example, trying to convert a string that's not a number to an integer raises a `ValueError`. The `except` block will catch this exception and print the message, "That's not a valid number!" You can catch multiple exceptions by using multiple `except` statements.
```python
try:
# some code here
except ValueError:
# handle ValueError exception
except (TypeError, ZeroDivisionError):
# handle multiple exceptions
except:
# handle all other exceptions
```
Note that 'except:' catches all kinds of exceptions which might not be a good practice as you might end up catching unexpected errors. It's generally better to catch and handle exceptions that you understand and anticipate.
A `finally` block can be added at the end which will always execute after try and except blocks, regardless whether an exception has been raised or not. This is often used for cleanup code.
```python
try:
x = int('five')
except ValueError:
print("That's not a valid number!")
finally:
print("Done processing.")
```
In addition to this, there's the `else` clause which executes if the try block does not raise any exception.
```python
try:
x = int('5')
except ValueError:
print("That's not a valid number!")
else:
print("No exception occurred.")
finally:
print("Done processing.")
```
In this code, "No exception occurred." will be printed, because converting '5' to an integer does not raise a ValueError. The `finally` block is executed no matter what and "Done processing." will be also printed.
Understanding these control structures for handling exceptions will allow you to write more robust Python code. It's always good to anticipate and handle possible exceptions, providing thoughtful error messages to help with debugging.
