What is the difference between isset and empty?

Question

What is the difference between !isset and empty, isset and !empty ??

http://virendrachandak.wordpress.com/2012/01/21/php-isset-vs-empty-vs-is_null/ first hit at google "php isset vs empty" — clentfort, Jun 03 '12 at 13:23
possible duplicate of [isset() or !empty() functions on all variables in your views? PHP](http://stackoverflow.com/questions/1938061/isset-or-empty-functions-on-all-variables-in-your-views-php) — mario, Jun 03 '12 at 14:03
or [Why check both isset() and !empty()](http://stackoverflow.com/questions/4559925/why-check-both-isset-and-empty) — mario, Jun 03 '12 at 14:03
The link in the first comment for "php isset vs empty" has been updated to http://www.virendrachandak.com/techtalk/php-isset-vs-empty-vs-is_null/ — Virendra, Aug 16 '14 at 00:43

score 17 · Answer 1 · edited Jul 21 '12 at 15:11

17

The type comparison tables should answer all questions about these operators: http://php.net/manual/en/types.comparisons.php

edited Jul 21 '12 at 15:11

answered Jun 03 '12 at 13:27

mjhennig

I didn't realize that `$x = "";` and `$x = null;` produced different results. That's handy information to have. – doubleJ Jan 28 '13 at 20:16

score 2 · Answer 2 · answered Jun 03 '12 at 13:40

The basic answer would be that a variable can be set (not NULL) and yet be empty(can be assimilated to 0). Consider an empty array for example.

From the link presented by @mjhennig, you can see that 0 is considered to be empty. So is False and the empty string(obviously) :)

2 Answers2