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PHP array_filter() function (with example)

Hey everyone,

I am relatively new to PHP and I have been learning about arrays. Recently, I came across the "array_filter()" function in PHP and I am a bit confused about how it works.

I understand that array_filter() is used to filter out elements of an array based on a callback function. But I would really appreciate it if someone could provide me with a clear example to help me fully grasp the concept.

If possible, could you also explain any additional parameters that can be used with this function? I want to make sure I am using it correctly.

Thank you so much for your help in advance!

All Replies


Hey there,

I'd like to share my personal experience with the array_filter() function and provide you with another example to help you understand it better.

In one of my recent projects, I had to work with an array of user data. Let's say we had an array with user information like names, ages, and email addresses:

$users = [
["name" => "John", "age" => 25, "email" => "john@example.com"],
["name" => "Sarah", "age" => 32, "email" => "sarah@example.com"],
["name" => "Dave", "age" => 20, "email" => "dave@example.com"],

Now, let's assume we wanted to filter out users who are above a certain age, let's say 30. We can use the array_filter() function to achieve this:

$filteredUsers = array_filter($users, function($user) {
return $user["age"] > 30;

Based on the condition in our callback function, this will create a new array called `$filteredUsers` which will only contain users with an age greater than 30. In our case, the filtered array would contain only the second user, Sarah.

It's worth mentioning that apart from using a simple anonymous function as the callback, you can also use a named function as the callback. This can make your code more organized and reusable.

Another aspect to note is that you can also pass additional parameters to the callback function after the array parameter when using array_filter(). These additional parameters can be helpful if you need to add extra conditions or values from outside the callback function.

I hope this example sheds more light on how to use array_filter() effectively. If you have any further questions or need any clarifications, feel free to ask!

Best regards,


Hey there,

I'd be happy to help you understand the array_filter() function and provide you with an example from my personal experience.

So, array_filter() is a really handy function in PHP that allows you to filter an array by applying a callback function to each element. It creates a new array that only contains the elements that pass the callback's condition.

Here's a simple example to illustrate how it works. Let's say we have an array of numbers:

$numbers = [1, 2, 3, 4, 5];

Now, let's say we want to filter out all the even numbers from this array. We can use array_filter() to achieve this:

$filteredNumbers = array_filter($numbers, function($number) {
return $number % 2 == 0;

In this example, the callback function checks if a number is divisible by 2, indicating it's an even number. If the condition is true, the number is included in the new filteredNumbers array. In our case, the filteredNumbers array would contain [2, 4].

Now, let me explain some additional parameters that can be used with array_filter():

The second optional parameter of array_filter() is the callback function, which we used in our example. However, if you omit this parameter, array_filter() will remove all the elements from the array that are equivalent to false (e.g., empty strings, null values, zeros, etc.).

Additionally, you can use a third optional parameter to specify a flag that determines how the callback function treats the array's keys. If you don't provide this parameter, the keys are preserved in the filtered array. But if you set this flag to ARRAY_FILTER_USE_BOTH, the callback function will receive both the value and the key as arguments.

I hope this explanation and example help you understand how array_filter() works and how you can use it in your PHP projects. If you have any further questions, feel free to ask!

Best regards,


Hey there!

I just wanted to jump in and share my personal experience with array_filter() to give you another perspective.

In one of my recent projects, I was working with an array of products. Each product had various attributes like name, price, and stock availability. My goal was to filter out only the products that were in stock.

Here's a simplified example of my array:

$products = [
["name" => "iPhone", "price" => 999, "stock" => true],
["name" => "Headphones", "price" => 99, "stock" => false],
["name" => "Keyboard", "price" => 49, "stock" => true],

To achieve the desired result, I utilized array_filter() along with a callback function:

$inStockProducts = array_filter($products, function($product) {
return $product["stock"] === true;

By using this approach, a new array named `$inStockProducts` will only contain the products that have the "stock" attribute set to true. In our array above, the resulting array would only include the "iPhone" and "Keyboard" products.

It's worth mentioning that apart from using anonymous functions as callbacks, you can also utilize named functions for the callback. This can make your code more readable and maintainable, especially for complex filtering conditions.

Lastly, it's important to note that array_filter() preserves the keys of the original array. So, if you need to reset the keys, you can use array_values() on the resulting array to re-index them.

I hope my personal experience with array_filter() and this example have provided you with additional insights. If you have any further questions, feel free to ask!

Best regards,

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