The empty() function is an built-in function in PHP which is used to check whether a variable is empty or not. A variable is empty if it does not exist or if its value equals false.

Note:

The empty() function does not create a warning if the variable does not exist which means empty() is equivalent to !isset($var) || $var == false.

List of empty Value :

  • 0 – 0 as an integer
  • “0” – 0 as a string
  • “” – An empty string
  • 0.0 – 0 as a float
  • NULL
  • FALSE
  • array() – An empty array
  • $var_name; – A variable declared but without a value in a class

Example:

<?php
$var1 = 0;
$var2 = NULL;
$var3 = FALSE;
$var4 = 'PHP Tutorials';
$var5 = array();
$var6 = '';

// Testing the variables
if(empty($var1)){
echo '$var1 is empty.'; //Output: $var1 is empty.
}
echo "<br>";

if(empty($var2)){
echo '$var2 is empty.'; //Output: $var2 is empty.
}
echo "<br>";

if(empty($var3)){
echo '$var3 is empty.'; //Output: $var3 is empty.
}
echo "<br>";

if(empty($var4)){
echo '$var4 is empty.';
}
else
{
echo '$var 4 is not empty'; //Output: $var4 is not empty.
}
echo "<br>";

if(empty($var5)){
echo '$var5 is empty.'; //Output: $var5 is empty.
}
echo "<br>";
if(empty($var6)){
echo '$var6 is empty.'; //Output: $var6 is empty.
}
?>

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