PHP is not only a powerful language for web development, but also a treasure trove of built-in functions. These functions often become indispensable tools in everyday work. They allow you to solve routine tasks quickly, elegantly, and without excessive code. In this article, we will look at 10 really useful PHP functions that every developer, from beginners to confident professionals, should have in their arsenal.
array_filter() — filtering without unnecessary code
One of the most frequently used functions when working with arrays. With its help, you can easily filter out unnecessary elements, leaving only those that meet the specified conditions. This is especially useful when working with data from a form, API, or database, when it is important to get rid of “empty” or “unnecessary” values.
When it comes in handy: removing empty values, filtering by conditions (for example, leaving only positive numbers or records with a certain status).
array_map() — transforming arrays on the fly
This function allows you to quickly transform each element of an array. For example, you can multiply all numbers by 2, convert strings to uppercase, add a prefix to each element — all without an explicit loop.
Where it helps: preparing data before sending it to an external service, formatting data for the front end, massively changing the structure of an array.
implode() — convert an array into a string
If you need to convert an array into a string with a specific separator, this is the function you need. It is often used when generating meta tags, URL strings, CSV, or when displaying data in templates.
Typical tasks: collecting a list of tags, keywords, categories, or user names into a single string.
explode() — splits a string into an array
The opposite operation to the previous function. Useful in situations where you need to parse a string, such as a list of values obtained from a form or file. Allows you to instantly get an array from a string using a specified separator.
Examples: parsing parameters, keywords, lists of email addresses, coordinates, and other data.
str_contains() — searching for a substring in a human-friendly way
This function appeared relatively recently and immediately made life easier for developers. Checking whether a string contains the desired word or character has become much easier and clearer than with the old methods using strpos.
Where it is relevant: filtering records by content, validating strings, working with headers, logs, URLs.
str_replace() — quick replacements in a string
Replacing one or more fragments in a string is a common task. This function is ideal for adapting or “cleaning up” text. You can easily replace one word with another, remove unwanted characters, or adapt a string to the desired format.
Examples: auto-replacing prohibited words, correcting templates, transforming data before display.
json_encode() and json_decode() — working with JSON without pain
These two functions have become standard when working with external APIs, storage, and frontend. One converts an array or object into a string in JSON format, the other does the opposite. This makes it easy to exchange data between the backend and frontend, save complex structures to the database, and process them back.
Typical use cases: sending data in JavaScript, working with external APIs (REST), saving settings or sessions.
in_array() — checking for the presence of a value
A very simple but indispensable function when you need to make sure that a certain value is contained in an array. Especially relevant for validation, filtering, or access rights checking.
Examples: checking whether an item is in the cart, whether a user belongs to a certain group, whether the desired item is selected.
array_reduce() — converting an array into a single value
This function may seem complicated at first glance, but its power becomes apparent when you need to aggregate data: for example, to calculate a sum, combine strings, or find the maximum value. It “collapses” an array into a single value, applying a specified logic at each step.
Useful for: calculations, statistics, counting, generating results and reports.
strtotime() — working with dates without pain
One of the most flexible functions for working with dates. It can interpret almost any readable date and time format and convert it into an internal timestamp. This makes it easy to compare dates, calculate intervals, and format the result.
Where it comes in handy: when processing user input, working with external systems, generating schedules and events.
Conclusion
Knowing these built-in functions not only allows you to write less code, but also makes it more readable, secure, and maintainable. PHP is a language that already has solutions for most tasks, and the better you know the standard tools, the less you will have to “reinvent the wheel.”
If you aspire to a professional level in development, pay attention not only to frameworks and libraries, but also to a deep understanding of the language itself.