Empty value

[zzz]

Is this

if (empty($var)) { ... }

the same as this:

if ($var == '') { ... }

😕

[laserlight]

No, they are not the same. You've been around long enough to not be a newbie, so RTFM :p

[zzz]

Yes, I've been around long enough but still have my 'dah' moments. What's RTFM again?

🆒

[laserlight]

Read The Friendly Manual, in this case concerning [man]empty[/man].

[zzz]

Ah-ha... I read that manual quite frequently, but sometimes, having no formal coding training just keeps me from grasping simple things, like the one above. To me $a='' looks like empty($a) but somehow it's not... Back to TFM.

[laserlight]

It is okay, I just find it ironic that an experienced coder like yourself asks questions in the Newbies forum while real newbies ask their questions in the Coding forum and such :o

[NogDog]

Functionally, both will have the same effect: they will return TRUE if $var is an empty string, if $var is equal to zero or to boolean FALSE or NULL, or if $var is not set. However, empty() will not generate a notice-level error if $var is not set, whereas the '==' comparison will generate such an error.

If an explicit value of zero (0, 0.0, '0') is to be considered valid while an empty string is not, then you do not want to use either of those methods. You'll instead want to make use of the '===' identical operator, e.g.:

if(!isset($_POST['field']) or trim($_POST['field']) === '')
{
   $error = TRUE;
   echo "<p class='error'>You must enter a value for <b>Field</b>.</p>\n";
}

[laserlight]

However, empty() will not generate a notice-level error if $var is not set, whereas the '==' comparison will generate such an error.

Precisely, and that is stated in the manual as:

empty() is the opposite of (boolean) var, except that no warning is generated when the variable is not set.