Python except

The except keyword defines a block of code that executes when an error occurs in the associated try block, allowing the program to handle exceptions gracefully.

Syntax

try:
  # code that might raise an exception
except:
  # code to handle the exception

A specific exception type can also be mentioned as follows:

try:
  # code that might raise an exception
except ExceptionType:
  # code that runs if the specified exception occurs

Parameters:

• ExceptionType (optional): Specifies the type of exception to catch (e.g., ValueError, ZeroDivisionError).

Return value:

• The except block itself does not return a value.
• It executes code when the associated try block raises a matching exception.

Working of the try-except block

In the try block, code that might cause an error is executed. If an error occurs, the flow jumps to the except block to handle it gracefully. Specifying an exception type in except limits handling to that particular error, allowing for more precise control.

Note: If no exception type is specified, the except block will catch all exceptions. It’s best to use specific exception types to avoid unintentionally hiding bugs or critical errors.

Example: Handling Index Error with a General except Block

This example attempts to access an invalid index in a list, triggering an error that is caught using a general except block to prevent the program from crashing:

try:
  array = [0, 1, 2]
  # list index out of range
  n = array[3]
except:
  print('An error occurred.')

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The output for this code block will be:

An error occurred.

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Codebyte Example

The following example demonstrates how the except block handles dividing by zero error:

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