How to determine whether a PHP array is empty or contains specific elements

PHP Array is a very commonly used data structure that can be used to store and manipulate a set of data. In actual development, we often need to determine whether an array is empty or contains specific elements. This article explains how to use PHP's built-in functions to accomplish these operations, and provides corresponding code examples.

First, let’s look at how to determine whether an array is empty. In PHP, you can use the empty() function to determine whether an array is empty. The empty() function accepts a parameter and returns true if the parameter is an empty array or does not exist, otherwise it returns false.

The following is a sample code:

<?php
$emptyArray = [];
$nonEmptyArray = [1, 2, 3];

var_dump(empty($emptyArray));         // 输出: bool(true)
var_dump(empty($nonEmptyArray));      // 输出: bool(false)
?>

In the above example, $emptyArray is an empty array and $nonEmptyArray is a non-empty array. By calling the empty() function to determine whether the two arrays are empty, you can get the corresponding results.

Next, let’s look at how to determine whether an array contains specific elements. In PHP, you can use the in_array() function to determine whether an array contains a specified value. The in_array() function accepts two parameters, the first parameter is the value to be found, and the second parameter is the array to search. Returns true if the specified value exists in the index array, false otherwise.

The following is a sample code:

<?php
$array = [1, 2, 3, 4, 5];
$searchValue = 3;
$notFoundValue = 6;

var_dump(in_array($searchValue, $array));           // 输出: bool(true)
var_dump(in_array($notFoundValue, $array));         // 输出: bool(false)
?>

In the above example, $searchValue is the value to be found, and $notFoundValue is a value that does not exist in the array. By calling the in_array() function to determine whether these two values ​​exist in the array, you can get the corresponding result.

In addition to using the in_array() function, we can also use the array_search() function to determine whether an array contains a specified element. The array_search() function accepts two parameters, the first parameter is the value to be found, and the second parameter is the array to search. If the specified value exists in the array, returns the key name of the element, otherwise returns false.

The following is a sample code:

<?php
$array = [1, 2, 3, 4, 5];
$searchValue = 3;
$notFoundValue = 6;

var_dump(array_search($searchValue, $array));      // 输出: int(2)
var_dump(array_search($notFoundValue, $array));    // 输出: bool(false)
?>

In the above example, $searchValue is the value to be found, and $notFoundValue is a value that does not exist in the array. By calling the array_search() function to determine whether these two values ​​exist in the array, you can get the corresponding results.

To summarize, you can use the empty() function to determine whether a PHP array is empty, and you can use the in_array() function or array_search() function to determine whether an array contains specific elements. The above is the introduction and sample code on how to determine whether a PHP array is empty or contains specific elements. I hope to be helpful!

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