How to convert an empty array and empty object to an empty string or null

问题

How can I convert an empty array to an empty string or null?

$empty_array = array();

var_dump($empty_array);

result,

array(0) { }

Also for an empty object below,

class null_object{};
$null_object = new null_object();
var_dump($null_object);

result,

object(null_object)#4 (0) { }

I am after null or just something like $empty_array = ''; whenever they are found empty.

回答1:

What about this:

function convert($array) {
    return (count($array) === 0) ? "" : $array;
}

$empty_array = array();
$empty_array = convert($empty_array);

This will simply convert it into a empty string if the array is empty.

An object is somewhat more complicated but you can just use get_object_vars():

function convert($object) {
    return (count(get_object_vars($object)) === 0) ? "" : $object;
}

Nb.: You cannot check an object on private variables.

回答2:

Using implode() for the simpler solution.

echo implode('',(array)$array_or_object);

来源：https://stackoverflow.com/questions/10471387/how-to-convert-an-empty-array-and-empty-object-to-an-empty-string-or-null