empty() function in PHP to check variable for null, zero value etc

Check empty values carefully

empty() is convenient when a missing or false-like value should be treated as empty. Remember that values such as 0 and the string '0' are also considered empty, so use a stricter comparison when zero is meaningful.

<?php
$quantity = 0;
if ($quantity === 0) {
    echo 'Quantity is zero';
}
?>

All statements below will return True for different values of variable $my_var

<?php
$my_var="";
if(empty($my_var)){echo " True Variable is empty, <br>";}
else {echo " False "; } 

$my_var="0";
if(empty($my_var)){echo " True Variable is empty, <br>";}
else {echo " False "; } 

$my_var=0;
if(empty($my_var)){echo " True Variable is empty,<br> ";}
else {echo " False "; } 

$my_var=0.0;
if(empty($my_var)){echo " True Variable is empty, <br>";}
else {echo " False "; } 


$my_var=Null;
if(empty($my_var)){echo " True Variable is empty, <br>";}
else {echo " False "; } 

$my_var=False;
if(empty($my_var)){echo " True Variable is empty,<br> ";}
else {echo " False "; } 

$my_var=array();
if(empty($my_var)){echo " True Variable is empty, <br>";}
else {echo " False "; } 
?>

Before using variable we can check the value by using empty function in PHP. The advantage of using empty function is it will not generate any error message if the variable does not exist.

This function empty() will return True or False ( Boolean return ) based on status of the variable.

if(empty($my_var)){echo " Variable is empty ";}<br>
else {echo " Variable is not empty ";}

The output of above command is here

Variable is empty

Note that there is no warning message. We will get True as return value from empty() if it is null data or 0 etc.

Here is a list for which we will get True as return value from empty() function after checking.

0
0.0
"0"
""
NULL
FALSE
array()

Examples

<?php
$my_var="";
echo empty($my_var);
?>

Output is

Difference between isset() and empty()

Include the commented line and check the difference.

<?php
$my_var = array();
// $my_var['some key']="Welcome "; // Include this line and check. 
if (empty($my_var['some key'])) {
  echo 'The value is either 0, empty, or not set at all<br>';
}else{
  echo 'This is not empty, value is '. $my_var['some key']. '<br>';
}

if (isset($my_var['some key'])) {
    echo 'True : Value is set';
}else{
	echo 'This is False';
}
?>

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empty(): Check variable is empty

Check empty values carefully

Examples

Difference between isset() and empty()

Subhendu Mohapatra