There are several types of arrays in php

In PHP, array is a very important data type. It can be used to save a set of data, and the elements in it can be found and modified based on the subscript. In PHP, arrays can be divided into the following types:

1. Indexed array (Numeric Array)

Indexed array is the most commonly used array type. In this kind of array , each element has a corresponding numeric index, which is used to represent the position of the element in the array. A numeric index can be a non-negative integer, which is a sequence of natural numbers starting from 0.

Example:

$nums = array(1, 2, 3, 4, 5);

In the above example, $nums is an index array, which Contains 5 elements, numbers 1 to 5 respectively.

2. Associative Array

Associative array is also called a dictionary array. It is an array with strings as keys. In an associative array, each element has a unique key that is used to identify and access the element.

Example:

$user = array(

'name' => 'Tom',
'age' => 20,
'sex' => 'male'

);

In the above example, $user is an associative array that contains 3 elements, namely 'name', 'age' and 'sex'. Elements in the array can be accessed by key name. For example, $user['name'] can get the name element in the array.

3. Multidimensional Array

Multidimensional array refers to an array composed of arrays. In PHP, you can create any multidimensional array of multiple levels. In this array type, each element can be an array or a basic type of data.

Example:

$matrix = array(

    array(1, 2, 3),
    array(4, 5, 6),
    array(7, 8, 9)

);

In the above example, $matrix is ​​a two-dimensional array that contains 3 arrays, each containing 3 elements. Elements in a multidimensional array can be accessed by using multiple indexes, for example $matrix1 can get the number 6 element in the array.

4. Natural Key Array

Natural key array refers to an index array without specifying a key name when creating the array. In this array type, PHP will automatically assign a key name to each element. This key name is the position number of the current element in the array.

Example:

$fruits = array('apple', 'banana', 'orange');

In the above example, $fruits is a natural key Name array, which contains 3 elements, namely 'apple', 'banana' and 'orange'. Since the key name is not specified when creating, PHP will automatically assign a key name to each element. This key name is the position number of the current element in the array.

Summary:

In PHP, arrays can be divided into four types: index arrays, associative arrays, multidimensional arrays and natural key arrays. In practical applications, choosing different types of arrays according to different needs can better achieve data storage and processing. No matter what type of array, it can be used to complete various practical data operation requirements.

The above is the detailed content of There are several types of arrays in php. For more information, please follow other related articles on the PHP Chinese website!