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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to list non-hidden files and directories in windows using Python?
Listing files and directories using Python is a common task in many applications, from file management tools to automated scripts. However, when we are working on the Windows Operating System, the hidden files and folders are marked using specific file attributes, which can clutter the output if not handled properly. Unlike Unix-based systems, where hidden files typically start with a dot such as .hidden) whereas Windows uses metadata to mark files as hidden. In this article, we'll explore several methods to list only non-hidden files and directories. Basic Filtering by Name Prefix This is the basic Filtering method, which checks ...
Read MoreHow expensive are Python dictionaries to handle?
Python dictionaries are very difficult to handle data. They use a special system called hashing, which allows quick access to information. This specifies the cost of different operations: Time Complexities of Dictionary Operations Python dictionaries are usually fast because they use hashing to find and store data. The time complexity of dictionary operations in Python depends on the size of the dictionary and the operations performed. Here are some of the common dictionary operations - ...
Read MoreWhat are the allowed characters in Python function names?
In Python, function names follow specific rules. A valid function name can only contain certain characters, and it must follow the naming conventions defined in the Python language syntax. Using the correct characters ensures that your code runs without syntax errors and stays readable. Allowed Characters in Function Names Python function names can consist of the following characters - Letters (A–Z, a–z) Digits (0–9) — but not at the beginning Underscores (_) — often used to separate words Function names must follow these rules - Must start with a letter or underscore Cannot start with a digit ...
Read MoreWhat is the difference between \\\'except Exception as e\\\' and \\\'except Exception, e\\\' in Python?
You can handle errors in Python using the try and except blocks. Sometimes, we also want to store the actual exception in a variable to print it or inspect it. This is done using the as keyword in modern Python. But if you have seen older code, you might find except Exception e or even except Exception, e being used. In this article, we will explore the difference between these syntaxes, understand why older ones no longer work in Python 3, and learn the best practices for clean exception handling. Understanding Basic Exception Handling Python provides try-except blocks to catch ...
Read MoreHow to raise Python exception from a C extension?
When writing a C extension for Python, you might need to raise an exception if something goes wrong in your C code. Python provides a special C API that helps you to raise errors in a way that works just like regular Python exceptions.This is helpful because even if your code is written in C for better performance, users can still handle errors using Python's normal try...except blocks. It makes your extension feel just like any other Python module.Using Python C API to Raise ExceptionsIn C extensions for Python, you can raise exceptions using the Python C API functions like ...
Read MoreHow to catch KeyError Exception in Python?
In Python, a KeyError exception occurs when a dictionary key that does not exist is accessed. This can be avoided by using proper error handling with the try and except blocks, which can catch the error and allow the program to continue running. Understanding KeyError in Python A KeyError is raised when you try to access a key that doesn't exist in a dictionary. It is one of the built-in exceptions that can be handled by Python's try and except blocks. Example: Accessing a non-existent key In this example, we are attempting to access a key that does not exist ...
Read MoreHow to return a json object from a Python function?
In Python, you need to use the built-in json module to work with JSON data. When you want to return data from a function in JSON format, you can use the json.dumps() function to convert a Python dictionary (or similar object) into a JSON string. This is helpful when making APIs, sending data in web responses, or saving organized data in files. Using json.dumps() Function The json.dumps function is used to convert a Python object (like a dictionary or list) into a JSON-formatted string. Syntax Following is its basic syntax - json.dumps(python_object) Where python_object is usually a dictionary or list ...
Read MoreWrite down a python function to convert camel case to snake case?
Camel case and snake case are ways of writing words together when we are programming. In camel case, we write words together without spaces and we start each new word with a capital letter except for the first word. For example, if we want to write a variable name for someone's date of birth, we can write it like this: dateOfBirth. In snake case, we write words together with an underscore symbol between them, and all the letters are lowercase. For example, if we want to write a variable name for someone's home address, we can write it like this: ...
Read MoreHow to pass arguments by value in Python function?
In Python, when you pass arguments to a function, they are passed by object reference. This means the function gets a reference (or pointer) to the actual object, not a copy of it. However, how this reference affects the object depends on whether the object is mutable or immutable. Mutable objects (like lists, dictionaries, and sets) can be changed inside the function. If you modify a mutable object inside the function, the changes will affect the original object outside the function as well. Immutable objects (like numbers, strings, and tuples) cannot be changed. If you try to modify ...
Read MoreHow to pass optional parameters to a function in Python?
In Python, you can pass optional parameters to functions, allowing you to call a function with fewer arguments than specified. Optional parameters are useful for providing default values when certain arguments are not provided. Python provides different ways to define optional parameters, including default values, variable-length argument lists, and keyword arguments. Using Default Arguments One common way to pass optional parameters is by setting default values for the parameters in the function definition. If no argument is passed for those parameters during the function call, the default value is used. Example In the following example, the greet() function has an ...
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