Skip to main content

Python Finally and else clauses

In Python, the else and finally clauses in exception handling provide additional ways to manage the flow of your program when exceptions occur. Here’s a detailed look at how they work and examples to illustrate their usage.

The else Clause

The else clause is used to specify a block of code that should run if no exceptions are raised in the try block. It is typically used for code that should only run if the try block succeeds.

Example:

try:
    result = 10 / 2
except ZeroDivisionError:
    print("Error: Division by zero is not allowed.")
else:
    print(f"Result is {result}")

In this example:

  • If the division is successful, the else block executes and prints the result.
  • If a ZeroDivisionError occurs, the except block executes, and the else block is skipped.

The finally Clause

The finally clause is used to specify a block of code that will always be executed, regardless of whether an exception was raised or not. This is useful for cleanup actions like closing files or releasing resources.

Example:

try:
    result = 10 / 0
except ZeroDivisionError:
    print("Error: Division by zero is not allowed.")
finally:
    print("This block will always execute.")

In this example:

  • The finally block executes regardless of whether an exception is raised in the try block or not.

Using else and finally Together

You can use both else and finally clauses in the same try block. Here’s an example to demonstrate how they work together:

Example:

try:
    with open('example.txt', 'r') as file:
        contents = file.read()
except FileNotFoundError:
    print("Error: File not found.")
except IOError:
    print("Error: An I/O error occurred.")
else:
    print("File read successfully:")
    print(contents)
finally:
    print("Finished file operation.")

In this example:

  • The try block attempts to open and read a file.
  • If the file is not found, the FileNotFoundError exception is caught and the corresponding message is printed.
  • If an I/O error occurs, the IOError exception is caught and the corresponding message is printed.
  • If no exceptions are raised, the else block executes, printing the contents of the file.
  • Regardless of the outcome, the finally block executes, printing "Finished file operation."

Summary

  • else Clause: Executes if no exceptions are raised in the try block.
  • finally Clause: Always executes, regardless of whether an exception was raised or not.

Using these clauses allows you to manage your code more effectively, ensuring that you have clearly defined paths for handling both successful and exceptional conditions, along with a guaranteed cleanup mechanism.

Comments

Post a Comment

Popular posts from this blog

Power BI tenant settings and admin portal

As of my last update, Power BI offers a dedicated admin portal for managing settings and configurations at the tenant level. Here's an overview of Power BI tenant settings and the admin portal: 1. Power BI Admin Portal: Access : The Power BI admin portal is accessible to users with admin privileges in the Power BI service. URL : You can access the admin portal at https://app.powerbi.com/admin-portal . 2. Tenant Settings: General Settings : Configure general settings such as tenant name, regional settings, and language settings. Tenant Administration : Manage user licenses, permissions, and access rights for Power BI within the organization. Usage Metrics : View usage metrics and reports to understand how Power BI is being used across the organization. Service Health : Monitor the health status of the Power BI service and receive notifications about service incidents and outages. Audit Logs : Access audit logs to track user activities, access requests, and administrative actions wit...
Post a Comment
Read more

Performance Optimization

Performance optimization in SQL is crucial for ensuring that your database queries run efficiently, especially as the size and complexity of your data grow. Here are several strategies and techniques to optimize SQL performance: Indexing Create Indexes : Primary Key and Unique Indexes : These are automatically indexed. Ensure that your tables have primary keys and unique constraints where applicable. Foreign Keys : Index foreign key columns to speed up join operations. Composite Indexes : Use these when queries filter on multiple columns. The order of columns in the index should match the order in the query conditions. Avoid Over-Indexing:  Too many indexes can slow down write operations (INSERT, UPDATE, DELETE). Only index columns that are frequently used in WHERE clauses, JOIN conditions, and as sorting keys. Query Optimization Use SELECT Statements Efficiently : SELECT Only Necessary Columns : Avoid using SELECT * ; specify only ...
Post a Comment
Read more

DAX UPPER Function

The DAX UPPER function in Power BI is used to convert all characters in a text string to uppercase. This function is useful for standardizing text data, ensuring consistency in text values, and performing case-insensitive comparisons. Syntax: UPPER(<text>) <text>: The text string that you want to convert to uppercase. Purpose: The UPPER function helps ensure that text data is consistently formatted in uppercase. This can be essential for tasks like data cleaning, preparing text for comparisons, and ensuring uniformity in text-based fields. E xample: Suppose you have a table named "Customers" with a column "Name" that contains names in mixed case. You want to create a new column that shows all names in uppercase. UppercaseName = UPPER(Customers[Name]) Example Scenario: Assume you have the following "Customers" table: You can use the UPPER function as follows: Using the UPPER function, you can convert all names to uppercase: UppercaseName = ...
Post a Comment
Read more