Technology Tales

Count the number of posts in the custom post type in WordPress

WordPress provides several methods to count posts within custom post types, with WP_Query being a flexible approach that uses parameters such as category_name and post_type to retrieve specific data. This class requires defining these variables in an array, which is then passed to the WP_Query constructor to generate an object that includes the total number of posts found.

Alternatively, wp_count_posts offers a simpler way to count posts based on their status, such as published or drafted, but it does not support filtering by category slugs. The get_posts function can also be used, though it is less efficient for large datasets due to its tendency to load all posts into memory before counting. Each method has distinct use cases, with WP_Query generally preferred for its versatility in handling complex queries involving custom taxonomies and post types.

R Error: Can’t rename columns that don’t exist.

When using both the plyr and dplyr packages in R, a conflict can arise with the rename function, as both packages contain a function of the same name. Because R defaults to the most recently loaded package, using the rename function after loading dplyr last will trigger the error "Can't rename columns that don't exist" if the code was written with the plyr version in mind. The fix is straightforward: by explicitly specifying the package name before the function using the format plyr::rename, R is directed to use the correct version, allowing column renaming to proceed without error.

Avoid loops in R! Really?

A common belief among R programmers is that loops are slow and should always be replaced with vectorised calculations or apply family functions such as sapply. Benchmarking tests comparing vectorised calculations, naive loops and vapply across two tasks, calculating square roots and formatting numbers with paste, reveal a more nuanced picture.

Vectorised calculations remain the fastest option for simple mathematical operations, running more than ten times faster than a loop, but vapply performs notably worse than a naive loop in that same scenario. For more complex functions like paste, the performance gap narrows considerably, with loops taking only around 50% longer than the vectorised approach and vapply performing at roughly the same speed as a loop.

The conclusion drawn is that vectorisation should be used where available, but choosing apply-family functions over loops for the sake of speed alone is not well justified. Instead, the preference for apply family functions is better understood as a matter of coding style and readability rather than performance.

SS64 is a reference guide created by Simon Sheppard that offers syntax examples and documentation for commonly used database and operating system commands. It covers areas including SQL Server and MySQL, and is regularly updated, with recent additions including PowerShell colour options and chmod references.

Flask is a lightweight WSGI web application framework designed to facilitate rapid development and scalability, relying on dependencies such as Werkzeug, Jinja and Click. Its documentation provides comprehensive guidance on installation, a quick-start guide for initial setup and a detailed tutorial for building applications, alongside sections covering configuration, testing, error handling, deployment and security considerations. Additional resources include API references, explanations of design decisions, extension development practices and information on contributing to the project, with a focus on modular application structures, command-line interfaces and asynchronous capabilities through technologies like Gevent. The framework supports a range of features, from session management and template rendering to handling HTTP methods and deploying to production environments, while also addressing best practices for configuration, logging and application lifecycle management.

Gunicorn

A Python-based WSGI HTTP server designed for deploying web applications, this tool is known for its reliability in production environments and ease of use, requiring minimal configuration. It supports multiple frameworks including Django, Flask and FastAPI and offers various worker types to handle different workloads, from synchronous processing to asynchronous handling of I/O-bound tasks. The software is compatible with both WSGI and ASGI standards, allowing integration with a range of application stacks without modification. It provides documentation for deployment options such as Nginx, systemd and Docker, along with community support and resources for troubleshooting and contribution.

MySQL DELETE Query: How to Delete a Row from Table

The MySQL DELETE command is used to remove specific rows from a database table, with the WHERE clause allowing precise filtering to target particular entries. If omitted, all rows in the table are deleted, emphasising the need for caution and prior data backups to prevent irreversible loss. Examples demonstrate deleting individual records by specifying identifiers or multiple entries using the IN clause, highlighting the command's utility in managing obsolete or temporary data while underscoring the critical importance of ensuring data integrity through careful execution and backup practices.

MySQL Change a User Password Command Tutorial

Changing a MySQL or MariaDB user password on Linux, Unix, macOS and Windows systems can be achieved through several command line methods. The primary approach involves logging into the MySQL server as a root or admin user and running an ALTER USER command followed by a FLUSH PRIVILEGES command to reload the grant tables.

For older versions of MySQL, specifically 5.7.5 and earlier, the SET PASSWORD syntax or an UPDATE command targeting the mysql.user table can be used instead. An alternative method involves the mysqladmin command line tool, which allows password changes to be made directly from the shell without needing to enter the MySQL prompt.

It is worth noting that in MySQL 5.7 and later, the Password field in the user table was replaced with authentication_string, and FLUSH PRIVILEGES is not strictly necessary when using account management statements such as ALTER USER, as the server automatically reloads the grant tables in those cases.

Julia Programming: a Hands-on Tutorial

Julia is a free, open-source, general-purpose programming language originally developed by researchers at MIT, designed to combine the speed of compiled languages like C and Fortran with the ease of use associated with Matlab and Python. It achieves this through a just-in-time compiler, meaning code that appears interpreted runs at speeds comparable to fully compiled alternatives, often with significantly fewer lines of code required. The language supports optional typing, offers clean mathematical syntax and benefits from a thriving package ecosystem, making it particularly well-suited to scientific and engineering applications.

Hugo and Data: Advanced Manipulation with Slices and Maps

Advanced data manipulation in Hugo using Slices and Maps is a topic that receives little attention in the Hugo community, yet it is critical for building pages from remote sources such as API endpoints or Markdown files. Slices, which function as ordered arrays, can be created, appended to and filtered using built-in Hugo functions such as slice, append, uniq, first, last and where, while the index function allows retrieval of specific elements. Maps, which are associative arrays of key and value pairs, can be created using the dict function and combined using merge, with the reflect.IsSlice and reflect.IsMap functions available for type checking.

When slices and maps are combined, developers can construct structured data collections that can be browsed using range loops, filtered using where clauses with operators such as in and intersect, and sorted in ascending or descending order using the sort function. While hard-coding data in this way is useful for defining defaults and reusable bases, real-world projects typically draw data from external sources such as APIs or user-managed content files, with more advanced transformation techniques building upon these foundational concepts.