Explore how many types of arrays there are in PHP

In PHP, array is a very common data structure, which is very convenient for storing and manipulating data. PHP arrays can store any type of data, including strings, integers, floating point numbers, etc. Arrays are a very important concept, so today we will explore how many types of arrays there are in PHP.

In PHP, arrays are divided into the following 3 types:

1. Index array

Index array is the most common array type in PHP . It is an array of consecutive numeric key-value pairs, and individual values ​​can be accessed via subscripts. In PHP, if no key value is specified, PHP will automatically generate a default numeric key value, starting from 0 and increasing. The definition format of the index array is as follows:

$array = array(value1, value2, value3, ...);

or:

$array = [value1, value2, value3, ...];

For example:

$cars = array("Volvo", "BMW", "Toyota");

You can access the elements in the array through subscripts:

echo $cars[0]; // 输出 "Volvo"

2. Associative array

Associative array is also called hash array, which is an array with strings as key values. The definition format of an associative array is as follows:

$array = array(key1 => value1, key2 => value2, key3 => value3, ...);

or:

$array = [key1 => value1, key2 => value2, key3 => value3, ...];

For example:

$age = array("Peter"=>"35", "Ben"=>"37", "Joe"=>"43");

You can access the elements in the array through the key name:

echo "Peter is " . $age['Peter'] . " years old.";

3. Multidimensional array

Multidimensional array is a very flexible data structure in PHP. Multiple arrays can be nested. Each array can be an index array, an associative array, or another multidimensional array. . For multi-dimensional arrays, we often use loop statements to iterate through all elements. The definition format of a multidimensional array is as follows:

$array = array(
    array(value1, value2, value3, ...),
    array(value1, value2, value3, ...),
    ...
);

For example:

$cars = array(
    array("Volvo",22,18),
    array("BMW",15,13),
    array("Saab",5,2),
    array("Land Rover",17,15)
);

You can access the elements in a multidimensional array through two subscripts:

echo $cars[0][0].": In stock: ".$cars[0][1].", sold: ".$cars[0][2].".<br>";

In PHP, the array is A very important concept with wide application and importance. The three types of arrays introduced above are very common and frequently used. Skilled PHP developers can skillfully use arrays to handle complex data structures and develop more efficient applications.

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