How to determine if an array is empty in php

In PHP, it is not difficult to determine whether an array is empty. There are usually many ways to achieve this purpose. Here are a few of them:

1. Use the empty() function

The built-in empty() function in PHP can check whether a variable Is "null value", this function returns a Boolean value, if the variable is undefined, the value is 0 or an empty string, the array is empty, NULL, then it returns true, otherwise it returns false. You can use the empty() function like the following sample code to determine whether the array is empty:

$array = array(); // initialize empty array
if (empty($array)) {
    echo 'The array is empty';
} else {
    echo 'The array is not empty';
}

2. Use the count() function

Another useful function is count(), which Can return the number of elements in an array. If the array is empty, zero is returned. The following is a sample code that uses the count() function to determine whether the array is empty:

$array = array(); // initialize empty array
if (count($array) == 0) {
    echo 'The array is empty';
} else {
    echo 'The array is not empty';
}

3. Use the isset() function

isset() function can check whether the variable has been set and is not null . Therefore, you can also use isset() function to check whether the array is empty. The following is a sample code that uses the isset() function to determine whether the array is empty:

$array = array(); // initialize empty array
if (!isset($array[0])) {
    echo 'The array is empty';
} else {
    echo 'The array is not empty';
}

4. Use the array_key_exists() function

array_key_exists() function to check whether the specified key value exists in the array . If it does not exist, return false. Therefore, you can use this function to check whether the first element of the array exists to determine whether the array is empty. The following is a sample code for using the array_key_exists() function to determine whether an array is empty:

$array = array(); // initialize empty array
if (!array_key_exists(0, $array)) {
    echo 'The array is empty';
} else {
    echo 'The array is not empty';
}

To sum up, the above four methods can all achieve the effect of determining whether a PHP array is empty. In actual programming, you should choose different methods according to your own needs.

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