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This article mainly shows you how to get the array size in PHP, the content is simple and easy to understand, and the organization is clear. I hope it can help you solve your doubts. Let Xiaobian take you to study and learn "How to get the array size in PHP".

Arrays are a powerful data type in PHP. Knowing how to get the size of an array is a useful skill. In this article, I'll give a quick overview of how arrays work, and then I'll delve into how to get the size of PHP arrays. If you already know what an array is, you can skip directly to the How to Get Array Size section.

What are arrays in PHP?

Before we dive into array sizes, we need to make sure we understand what arrays are. An array in PHP is a variable type that allows multiple data to be stored.

For example, if you want to store a simple string, you would use PHP string types:

$heading = 'PHP Array Length Tutorial';

However, if you want to store more individual data, you might consider using several string variables.

$heading = 'PHP Array Length Tutorial';$subheading = 'How to get an array size';$author = 'Jonathan Bossenger'

That's all well and good, but what if you need to store more data and quickly call up any items elsewhere in your code? This is where arrays come in handy. You can still store individual data, but use individual variables.

$post_data = array( 'PHP Array Length Tutorial', 'How to get an array size', 'Jonathan Bossenger');

Each item in the array can be referenced by its numeric key. Therefore, instead of calling a single variable, you can refer to a single array item through its numeric keys.

echo $post_data[0];

In PHP, array keys start at 0.

For more control, arrays also allow you to define your own array keys using strings.

$post_data = array( 'heading' => 'PHP Array Length Tutorial', 'subheading' => 'How to get an array size', 'author' => 'Jonathan Bossenger');

This allows you to also reference array items through their string keys.

echo $post_data['heading'];

You can also define arrays using a new short array notation similar to JavaScript:

$post_data = [ 'heading' => 'PHP Array Length Tutorial', 'subheading' => 'How to get an array size', 'author' => 'Jonathan Bossenger'];

Arrays can also be nested to form more complex array variables:

$post_data = [ 'heading' => 'PHP Array Length Tutorial', 'subheading' => 'How to get an array size', 'author' => [ 'name' => 'Jonathan Bossenger', 'twitter' => 'jon_bossenger', ]];

Also, you can invoke specific array values using their nested keys:

echo $post_data['author']['name'];

However, if you find yourself doing this often, you might want to consider using objects instead of arrays.

Arrays are useful if you need to quickly collect and use different related data in one function or pass it to another.

By putting this data into arrays, you define fewer variables and can make your code easier to read and understand later. Passing a single array variable to another function is also much easier than passing multiple strings.

$post_data = [ 'heading' => 'PHP Array Length Tutorial', 'subheading' => 'How to get an array size', 'author' => [ 'name' => 'Jonathan Bossenger', 'twitter' => 'jon_bossenger', ]];$filtered_post_data = filter_post_data($post_data) How to get array size in PHP

Usually, when we talk about the size of an array, we're talking about how many elements exist in that array. There are two common ways to get the size of an array.

The most popular method is to use the PHP count() function. As the function name says, count() returns the count of array elements. But how we use the count() function depends on the array structure.

Let's look at the two sample arrays we defined earlier.

$post_data = array( 'heading' => 'PHP Array Length Tutorial', 'subheading' => 'How to get an array size', 'author' => 'Jonathan Bossenger');echo count($post_data);

In this example, count($post_data) results in 3. This is because there are three elements in the array: 'heading','subheading'and' author'. But what about our second nested array example?

$post_data = [ 'heading' => 'PHP Array Length Tutorial', 'subheading' => 'How to get an array size', 'author' => [ 'name' => 'Jonathan Bossenger', 'twitter' => 'jon_bossenger', ]];echo count($post_data);

Believe it or not, count($post_data) will also return 3 in this example. This is because by default, the count() function only evaluates the top-level array elements.

If you look at the function definition, you'll see that it takes two arguments--the array to be evaluated and a mode integer. The default value for this pattern is the predefined constant COUNT_NORMAL, which tells the function to evaluate only the top-level array elements.

If we change COUNT_RECURSIVE to pass predefined constants, it will run all levels of nesting and count them.

$post_data = [ 'heading' => 'PHP Array Length Tutorial', 'subheading' => 'How to get an array size', 'author' => [ 'name' => 'Jonathan Bossenger', 'twitter' => 'jon_bossenger', ]];echo count($post_data, COUNT_RECURSIVE);

Now count($post_data, COUNT_RECURSIVE) As expected, the result will be 5.

"But wait! "I heard you crying. "You mentioned there was another way? "。

Yes, another function you can use is sizeof(). However, sizeof() is just an alias for count(), and many people think (rightly so) that sizeof() will return the memory usage of an array.

So it's better to stick with count(), which is a name more appropriate for what you're doing-counting elements in an array.

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