Fixing the PHP empty function

Question

PHP has the habit of evaluating (int)0 and (string)"0" as empty when using the empty() function. This can have unintended results if you expect numerical or string values of 0. How can I "fix" it to only return true to empty objects, arrays, strings, etc?

Answer 1

This didn't work for me.

if (empty($variable) && '0' != $variable) {   // Do something } 

I used instead:

if (empty($variable) && strlen($variable) == 0) {   // Do something } 

Answer 2

I seldom use empty() for the reason you describe. It confuses legitimate values with emptiness. Maybe it's because I do a lot of work in SQL, but I prefer to use NULL to denote the absence of a value.

PHP has a function is_null() which tests for a variable or expression being NULL.

$foo = 0; if (is_null($foo)) print "integer 0 is null!\n";  else print "integer 0 foo is not null!\n";  $foo = "0"; if (is_null($foo)) print "string '0' is null!\n";  else print "string '0' is not null!\n";  $foo = ""; if (is_null($foo)) print "string '' is null!\n";  else print "string '' is not null!\n";  $foo = false; if (is_null($foo)) print "boolean false is null!\n";  else print "boolean false is not null!\n"; 

You can also use the exactly equals operator === to do a similar test:

if ($foo === null) print "foo is null!\n"; 

This is true if $foo is NULL, but not if it's false, zero, "", etc.