Introduction to Python Try Except
Python Try Except
The try
-except
statement is used for exception handling.
It allows you to catch and handle exceptions that may occur during the execution of your code, preventing your program from crashing.
Here's an overview of how to use try-except in Python:
Basic try
-except
Syntax
The basic syntax of the try
-except
statement is as follows:
try:
# Code block where an exception may occur
# ...
except ExceptionType:
# Code block to handle the exception
# ...
In this example:
In the
try
block, you place the code that may raise an exception. If an exception occurs within thetry
block, it is caught by theexcept
block, which contains the code to handle the exception.The
ExceptionType
is the specific type of exception you want to catch. You can catch specific exceptions likeValueError
,TypeError
, or you can use the genericException
to catch all exceptions.
Handling Exceptions
Inside the except
block, you write the code to handle the exception.
This could include printing an error message, logging the exception, or taking appropriate actions to handle the error gracefully.
As an example:
try:
num1 = int(input("Enter a number: "))
num2 = int(input("Enter another number: "))
result = num1 / num2
print("Result:", result)
except ValueError:
print("Invalid input. Please enter a valid number.")
except ZeroDivisionError:
print("Division by zero is not allowed.")
In this example:
- The
try
block attempts to perform division based on user input. - If the user enters a non-numeric value, a
ValueError
exception is raised and caught by the firstexcept
block, which prints an error message. - If the user enters zero as the second number, a
ZeroDivisionError
exception is raised and caught by the secondexcept
block.
Handling Multiple Exceptions
You can handle multiple exceptions in a single try
-except
statement.
This can be useful when different exceptions require different handling logic.
As an example:
try:
# Code that may raise exceptions
# ...
except ExceptionType1:
# Code to handle ExceptionType1
# ...
except ExceptionType2:
# Code to handle ExceptionType2
# ...
You can have multiple except blocks to handle different exceptions. The first matching except
block is executed, and subsequent except
blocks are skipped.
Using else and finally
The try
-except
statement can also include an else
block and a finally
block.
The else
block is executed if no exceptions are raised in the try
block. The finally
block is always executed, regardless of whether an exception occurred or not.
As an example:
try:
# Code that may raise exceptions
# ...
except ExceptionType:
# Code to handle the exception
# ...
else:
# Code to execute if no exceptions occurred
# ...
finally:
# Code to always execute, regardless of exceptions
# ...
The else
block is optional, and the finally
block is often used for cleaning up resources or finalizing operations, such as closing files or releasing locks.