PHP, or Hypertext Preprocessor, is a powerful scripting language that significantly enhances your web development skills. With its ease of use and flexibility, PHP allows developers to create dynamic, interactive web applications that can respond to user input in real time. This capability makes it an essential tool in modern web development, as it enables you to integrate databases, manage session data, and build features that elevate user experience. Mastering PHP creates a strong foundation for learning other programming languages and frameworks, thus broadening your skill set.

Moreover, PHP's extensive community support and comprehensive documentation make it easy for developers of all levels to find resources and solutions to common problems. By utilizing PHP's features, such as object-oriented programming, error handling, and various built-in functions, you can develop robust applications with less code. Additionally, platforms like WordPress and Laravel are built on PHP, offering practical examples of its application and encouraging you to dive deeper into your web development skills.

When it comes to PHP development, understanding the core functions is essential for writing efficient and effective code. Here are 10 essential PHP functions that every developer should know:

1. strlen() - This function returns the length of a string, making it useful for validating inputs.
2. array_push() - This function adds one or more elements to the end of an array, which is crucial for dynamic data management.
3. implode() - It joins array elements into a string, facilitating easy output and data handling.
4. explode() - This function splits a string by a specified separator, perfect for parsing data.
5. json_encode() - Use this function to convert PHP arrays and objects into JSON format, commonly used in APIs.

In addition to these, other vital functions include:

6. header() - It is used to send raw HTTP headers, crucial for redirection and content type management.
7. mysqli_connect() - This function establishes a connection to a MySQL database, a foundational aspect of many applications.
8. var_dump() - This is invaluable for debugging, allowing developers to display structured information about one or more variables.
9. date() - It formats a local date and time, important for time management in applications.
10. isset() - This function checks if a variable is set and is not null, aiding in input validation and error prevention.

Mastering these 10 essential PHP functions can greatly enhance your coding efficiency and effectiveness.

As we delve into the landscape of modern web development, a common question arises: Is PHP still relevant? Despite the emergence of various programming languages and frameworks, PHP continues to be a powerful and widely-used server-side scripting language. With over 78% of websites utilizing PHP, including major platforms like WordPress and Facebook, it proves its endurance in delivering robust functionalities. Its simplicity, combined with extensive community support and a plethora of frameworks such as Laravel and Symfony, makes PHP a strong contender in the ongoing web development race.

However, the debate around PHP's relevance goes beyond mere usage statistics. Developers are increasingly looking for features that enhance performance, scalability, and security. Although modern alternatives like Node.js and Python's Django have gained traction for their asynchronous capabilities and clean syntax, PHP has evolved significantly over the past few years. With the release of PHP 8, new features such as Just-In-Time (JIT) compilation and enhanced type system have positioned PHP firmly within the scope of contemporary web development practices. Ultimately, the choice of language often comes down to the specific needs of a project, making it clear that PHP continues to hold its ground in a diverse and ever-evolving tech landscape.