How to determine if an array is empty in php

In PHP, there are many ways to determine whether an array is empty. This article will explain several of them.

Method 1: Use the count function

PHP’s count function can count the number of elements in the array, so you can use this function to determine whether an array is empty. The specific implementation is as follows:

if (count($array) == 0) {
    // 空数组
} else {
    // 非空数组
}

In the above code, the value returned by count($array) is the number of elements in the array $array. If it is 0, it means The array is empty. If it is not 0, it means the array is not empty.

Method 2: Use empty function

PHP's empty function can check whether the variable is empty. If the variable does not exist, is 0, is false, is an empty string or an empty array, then Returns true, otherwise returns false. Therefore, you can use the empty function to determine whether an array is empty. The specific implementation is as follows:

if (empty($array)) {
    // 空数组
} else {
    // 非空数组
}

In the above code, empty($array) determines whether $array is empty. If it is empty, it returns true, which means the array is null. If it is not empty, it returns false, indicating that the array is not empty.

Method 3: Use the isset function

PHP’s isset function can determine whether a variable has been defined and is not null. Therefore, you can use the isset function to determine whether an array is empty. The specific implementation is as follows:

if (!isset($array) || count($array) == 0) {
    // 空数组
} else {
    // 非空数组
}

In the above code, isset($array) determines whether $array has been defined and is not null. If false, it means the array is empty. If it is true, continue to use the count function to determine whether the number of elements in the array is 0.

Method 4: Use the array_filter function

PHP’s array_filter function can filter the elements in the array, leaving only elements whose values ​​are not false. Therefore, if all elements in an array have the value false, array_filter will return an empty array. With this feature, you can use the array_filter function to determine whether an array is empty. The specific implementation is as follows:

if (empty(array_filter($array))) {
    // 空数组
} else {
    // 非空数组
}

In the above code, array_filter($array) filters the elements in the array $array, leaving only elements whose value is not false. If the filtered array is empty, it means the original array is empty. If the filtered array is not empty, it means the original array is not empty.

Method 5: Use foreach loop

Finally, if none of the above methods apply, you can use foreach loop to determine whether the array is empty. The specific implementation is as follows:

$isEmpty = true;
foreach ($array as $value) {
    if (!empty($value)) {
        $isEmpty = false;
        break;
    }
}

if ($isEmpty) {
    // 空数组
} else {
    // 非空数组
}

In the above code, the initial value of $isEmpty is true, which means the array is empty. Then, loop through each element in the array via a foreach, checking if it is empty. If it is found that an element is not empty, it means that the array is not empty, change the value of $isEmpty to false, and use break to exit the loop.

After explaining the above methods, I believe everyone has a deeper understanding of how to determine whether an array is empty. I hope it will be helpful to you.

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