Array functions in PHP8: Examples of various operations of array_map()

PHP is a commonly used server-side scripting language that is widely used in the field of web development. PHP 8 is the latest version of the PHP language, bringing many new features and performance optimizations. One of the most eye-catching improvements is the reconstruction of array functions, including improvements to some commonly used array functions such as array_map().

The array_map() function is used to apply a callback function to each element in the array and return a processed new array. In PHP 8, the array_map() function supports a variety of operations, and in this article we will introduce some examples.

1. Double the values ​​in the array

First, let’s look at how to use the array_map() function to double each value in the array. The following is a sample code:

<?php
// 定义数组
$numbers = [1, 2, 3, 4, 5];

// 定义回调函数
function double($n)
{
  return $n * 2;
}

// 使用array_map()函数执行操作
$result = array_map("double", $numbers);

// 输出结果
print_r($result);
?>

The running results are as follows:

Array
(
    [0] => 2
    [1] => 4
    [2] => 6
    [3] => 8
    [4] => 10
)

In this example, we define an array $numbers, which contains some numbers. Then, we define a callback function double() that multiplies each element in the array by 2 and returns the result. Finally, we use the array_map() function to apply the double() function as a callback function to each element in the $numbers array and generate a new array $result.

2. Format the values ​​in the array

Next, let’s look at how to use the array_map() function to format the values ​​in the array into a string. The following is a sample code:

<?php
// 定义数组
$numbers = [1, 2, 3, 4, 5];

// 定义回调函数
function format($n)
{
  return "Number " . $n;
}

// 使用array_map()函数执行操作
$result = array_map("format", $numbers);

// 输出结果
print_r($result);
?>

The running results are as follows:

Array
(
    [0] => Number 1
    [1] => Number 2
    [2] => Number 3
    [3] => Number 4
    [4] => Number 5
)

In this example, we define an array $numbers, which contains some numbers. Then, we define a callback function format(), which formats each element in the array into a string and returns the result. Finally, we use the array_map() function to apply the format() function as a callback function to each element in the $numbers array and generate a new array $result.

3. Convert the values ​​in the array

Finally, let’s see how to use the array_map() function to convert the values ​​in the array. The following is a sample code:

<?php
// 定义数组
$numbers = [1, 2, 3, 4, 5];

// 定义回调函数
function convert($n)
{
  if ($n % 2 == 0) {
    return "even";
  } else {
    return "odd";
  }
}

// 使用array_map()函数执行操作
$result = array_map("convert", $numbers);

// 输出结果
print_r($result);
?>

The running results are as follows:

Array
(
    [0] => odd
    [1] => even
    [2] => odd
    [3] => even
    [4] => odd
)

In this example, we define an array $numbers, which contains some numbers. Then, we define a callback function convert() that converts each element in the array to a string and returns the result. If the element is an even number, the string "even" is returned, otherwise the string "odd" is returned. Finally, we use the array_map() function to apply the convert() function as a callback function to each element in the $numbers array and generate a new array $result.

Summary

The array_map() function is one of the array functions in PHP 8, which supports a variety of operations. In this article, we introduced some examples of the array_map() function, including doubling the values ​​in the array, formatting the values ​​in the array into strings, converting the values ​​in the array, etc. These examples can help developers better understand and use the array_map() function and improve development efficiency.

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