How to use array return in PHP

During the development process, using arrays is a very common thing. Arrays in PHP have powerful functions and can store different types of data, such as numbers, strings, and even objects. The return value of an array is also very useful because it is convenient to obtain a value when needed and then pass that value to a function or other function. This article will introduce how to use array returns in PHP.

1. Define an array

In PHP, to define an array, you can use the following methods:

1. Index array

The index array is an array containing a series of values. Each value has a unique index, starting from 0 and increasing. To create an indexed array, you can use the following syntax:

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

where value1, value2,..., valueN represent the values ​​to be stored in the array.

For example, the following code creates an indexed array containing 3 elements:

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

2. Associative array

An associative array is an array containing key-value pairs An array where each key is a unique string or numeric value. To create an associative array, you can use the following syntax:

$array = array(key1=>value1, key2=>value2, ..., keyN=>valueN);

Among them, key1, key2,..., keyN represent the keys to be stored in the array, value1, value2,..., valueN represent the corresponding value.

For example, the following code creates an associative array containing 3 elements:

$prices = array("apple"=>0.99, "banana"=>0.59, "orange"=>0.79);

2. Array return

Array return refers to using an array as a function or method return value. To achieve this, define an array inside a function or method and return it. Next, let's look at how arrays are defined and returned from functions.

1. Define an array in a function

The following is the syntax for defining an array in a function:

function function_name() {
    $array = array(value1, value2, ..., valueN);
    return $array;
}

Among them, value1, value2,..., valueN represents the value to be stored in the array.

For example, the following code defines a function called get_fruits and inside the function an indexed array of 3 elements:

function get_fruits() {
    $fruits = array("apple", "banana", "orange");
    return $fruits;
}

2. Return array

To return an array from a function, simply use the return statement to return the previously defined array. The following is the syntax for returning an array:

function function_name() {
    $array = array(value1, value2, ..., valueN);
    return $array;
}

For example, the following code defines a function called get_fruits and returns a previously defined indexed array of 3 elements:

function get_fruits() {
    $fruits = array("apple", "banana", "orange");
    return $fruits;
}

3. Example

Next, you'll see some examples of how to use array returns.

1. Get a specific value in an array

To get a specific value in an array from a function, you can use a method that returns an array. For example, in the following code, the get_fruits function will return an indexed array containing 3 elements. In the main function, you can use the index operator to get the 2nd element in the array (i.e. banana) and print it to the screen:

function get_fruits() {
    $fruits = array("apple", "banana", "orange");
    return $fruits;
}

function main() {
    $fruits = get_fruits();
    $second_fruit = $fruits[1];
    echo $second_fruit;
}

main();    // 输出：banana

2. Traverse the array in a foreach loop

If you want to return an array in a function and iterate it in a foreach loop, you can use the method of returning an array. For example, in the following code, the get_prices function returns an associative array containing 3 elements. In the main function, you can use a foreach loop to iterate through the array and print the keys and values ​​to the screen:

function get_prices() {
    $prices = array("apple"=>0.99, "banana"=>0.59, "orange"=>0.79);
    return $prices;
}

function main() {
    $prices = get_prices();
    foreach ($prices as $fruit => $price) {
        echo $fruit . " costs " . $price . " dollars.\n";
    }
}

main();

The output is as follows:

apple costs 0.99 dollars.
banana costs 0.59 dollars.
orange costs 0.79 dollars.

3. Use the array return in other functions

If you want to use the array return value in other functions or methods, you can assign the returned array to a variable. For example, in the following code, the get_fruits function returns an indexed array of 3 elements, which is used in the get_fruit_count function. The get_fruit_count function counts the number of elements in the array and then prints the value to the screen:

function get_fruits() {
    $fruits = array("apple", "banana", "orange");
    return $fruits;
}

function get_fruit_count() {
    $fruits = get_fruits();
    $count = count($fruits);
    echo "There are " . $count . " fruits.\n";
}

get_fruit_count();

The output is as follows:

There are 3 fruits.

Summary

Arrays are the most common in PHP programming One of the data structures. Learning how to use array returns allows developers to utilize this functionality more effectively. In this article, you learned how to define an array, use array returns in functions, and how to use the returned array in other functions or methods. With this knowledge, you can easily use array return values ​​to achieve more efficient PHP programming.

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