Code to determine whether a PHP array is empty

PHP’s preferred method to determine if an array is empty: count($arr),size($arr);

Copy the code The code is as follows:

$arr= array("");
echo count($arr ; $arr);
//Output 0

PHP judgment array is empty method 2: empty($arr);

Copy code The code is as follows:

$arr= array("");
$result = empty($arr);
//$result = false
$arr = array();
$result = empty($arr);

//$result = true

These two methods are sufficient When it comes to judging whether simple arrays and multi-dimensional arrays are empty, I generally use empty() to judge whether the array is not empty, so that the code looks easier to understand. To determine whether the array is empty, just use this function count. If the output is 0, then the array is empty. The following is a simple test code. PHP code example to determine whether the array is empty

Copy the code

The code is as follows:


$arr = array();

echo count($arr);
?>

If the output is 0, the array is empty

PHP method 2 to determine if the array is empty: empty($arr);

Copy the code

The code is as follows:


$arr= array("");
$result = empty($arr);

//$result = false $arr = array();

$result = empty($arr);

//$result = true

PHP determines whether the array is empty , for loopThe simplest and most direct method is to use a for loop to traverse the array. It can be judged for arrays with known dimensions, but what should we do if it is an unknown multi-dimensional array?

PHP determines whether the array is empty, implode();

Use implode() to output the array as a string, and determine whether the output string is empty. At first glance, it seems to be a good method, but unfortunately, like the previous point, it does not work for arrays with more than two dimensions. For example:



Copy code

The code is as follows:

$arr= array(array(),array(),arr(www.jb51.net)ay());

$str = implode( ',',$arr);

if(empty($str)) echo "empty";

else echo "not empty";

Obviously $arr is a two-dimensional array containing three empty arrays, it should It is considered empty, but the output is indeed non-empty. Judgment failed.

PHP determines that the array is empty three, count();Copy the code

The code is as follows:


$arr= array("","","");
echo count($arr);

PHP determines that the array is empty, in_array('', $arr));

Copy the code The code is as follows:

$arr= array("d","s"," ");
echo in_array('', $arr);

This can only show that there are empty elements in the array, but cannot prove that the array is empty. Obviously not.

PHP determines that the array is empty, empty();

This cpyeh feels similar to the previous methods

Copy the code

The code is as follows:

$arr= array("","", "");if(empty($arr)) echo "empty";

else echo "not empty";

The result is still non-empty

PHP determines whether the array is empty. Six, use strlen(), no The length of the content seems to be 1We can also add print_r($arr); to the above example to see. The above has introduced the code to determine whether a PHP array is empty, including the relevant aspects. I hope it will be helpful to friends who are interested in PHP tutorials.