Why check both isset() and !empty()

Question

Is there a difference between isset and !empty. If I do this double boolean check, is it correct this way or redundant? and is there a shorter way to do the same thing?

isset($vars[1]) AND !empty($vars[1])

Answer 1

if we use same page to add/edit via submit button like below

<input type="hidden" value="<?echo $_GET['edit_id'];?>" name="edit_id">

then we should not use

isset($_POST['edit_id'])

bcoz edit_id is set all the time whether it is add or edit page , instead we should use check below condition

!empty($_POST['edit_id'])

Answer 2

The accepted answer is not correct.

isset() is NOT equivalent to !empty().

You will create some rather unpleasant and hard to debug bugs if you go down this route. e.g. try running this code:

<?php

$s = '';

print "isset: '" . isset($s) . "'. ";
print "!empty: '" . !empty($s) . "'";

?>

https://3v4l.org/J4nBb

Answer 3

"Empty": only works on variables. Empty can mean different things for different variable types (check manual: http://php.net/manual/en/function.empty.php).

"isset": checks if the variable exists and checks for a true NULL or false value. Can be unset by calling "unset". Once again, check the manual.

Use of either one depends of the variable type you are using.

I would say, it's safer to check for both, because you are checking first of all if the variable exists, and if it isn't really NULL or empty.