What is the difference between 'isset()' and '!empty()' in PHP?

Isset function

ISSET checks the variable to see if it has been set. In other words, it checks to see if the variable is any value except NULL or not assigned a value. ISSET returns TRUE if the variable exists and has a value other than NULL. That means variables assigned a "", 0, "0", or FALSE are set, and therefore are TRUE for ISSET.

Example

 Live Demo

<?php
   $val = '0';
   if( isset($val)) {
      print_r(" $val is set with isset function <br>");
   }
   $my_array = array();
   echo isset($my_array['New_value']) ?
   'array is set.' :  'array is not set.';
?>

Output

This will produce the following output −

0 is set with isset function
array is not set.

!empty function

EMPTY checks to see if a variable is empty. Empty is interpreted as: "" (an empty string), 0 (integer), 0.0 (float)`, "0" (string), NULL, FALSE, array() (an empty array), and "$var;" (a variable declared, but without a value in a class.

Example

 Live Demo

<?php
   $temp_val = 0;
   if (empty($temp_val)) {
      echo $temp_val . ' is considered empty';
   }
   echo "nn";
   $new_val = 1;
   if (!empty($new_val)) {
      echo $new_val . ' is considered set';
   }
?>

Output

This will produce the following output −

0 is considered empty 1 is considered set

AmitDiwan

e

Updated on: 07-Apr-2020

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