empty


php128 apg

DETERMINES whether a variable is EMPTY.





This function returns a BOOLEAN value when it tests the following variable types:

STRING, NUMERIC, BOOLEAN, ARRAY, NULL, RESOURCE or OBJECT.

One way to visualize the test result is to use var_dump.

A variable is considered empty if it does not exist or the BOOLEAN value returned is equals FALSE.

This function does not generate a WARNING if the variable does not exist.



<?php

bool empty ( mix $var );


where,

$var = VARIABLE to be checked

?>

$var


The variable to be checked.

The next table shows the values that are considered empty:

mix $var TYPE
"" STRING
"0" STRING
0 INTEGER
0.0 FLOAT
NULL NULL
FALSE FALSE
array() or [] ARRAY
ed48


  1 EXERCISE   

<?php

function is_empty($tvar)
{
if (empty($tvar))
{
var_dump($tvar);
echo '<br>is considered EMPTY!<br><br>';
}
else
{
var_dump($tvar);
echo '<br>IS NOT considered EMPTY!<br><br>';
}
}

$var1 = "";
$var2 = '';
$var3 = " ";
$var4 = ' ';
$var5 = 0;
$var6 = 0.0;
$var7 = "0";
$var8 = '0';
$var9 = NULL;
$varA = false;
$varB = array();
$varC = imagecreate(8,8);

is_empty($var1);
is_empty($var2);
is_empty($var3);
is_empty($var4);
is_empty($var5);
is_empty($var6);
is_empty($var7);
is_empty($var8);
is_empty($var9);
is_empty($varA);
is_empty($varB);
is_empty($varC);

?>

 RESULT   

string(0) ""
is considered EMPTY!

string(0) ""
is considered EMPTY!

string(1) " "
IS NOT considered EMPTY!

string(1) " "
IS NOT considered EMPTY!

int(0)
is considered EMPTY!

float(0)
is considered EMPTY!

string(1) "0"
is considered EMPTY!

string(1) "0"
is considered EMPTY!

NULL
is considered EMPTY!

bool(false)
is considered EMPTY!

array(0) { }
is considered EMPTY!

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
resource(10) of type (gd)
[PHP 7.4.XX] IS NOT considered EMPTY!

or

object(GdImage)#1 (0) { }
[PHP 8.0.XX] IS NOT considered EMPTY!
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -


<?php

!isset( mix $var ) || mix $var == FALSE )

mix $var = VARIABLE TO BE CHECKED



This is equivalent to:

bool empty ( mix $var );

?>

$var


The variable to be checked.



  2 EXERCISE   

<?php

function is_emptyn($tvarn)
{
if (!isset($tvarn) || $tvarn == FALSE)
{
var_dump($tvarn);
echo "<br>is considered EMPTY!<br><br>";
}
else
{
var_dump($tvarn);
echo "<br>IS NOT considered EMPTY!<br><br>";
}
}

$var01 = "";
$var02 = '';
$var03 = " ";
$var04 = ' ';
$var05 = 0;
$var06 = 0.0;
$var07 = "0";
$var08 = '0';
$var09 = NULL;
$var0A = false;
$var0B = array();
$var0C = imagecreate(8,8);

is_emptyn($var01);
is_emptyn($var02);
is_emptyn($var03);
is_emptyn($var04);
is_emptyn($var05);
is_emptyn($var06);
is_emptyn($var07);
is_emptyn($var08);
is_emptyn($var09);
is_emptyn($var0A);
is_emptyn($var0B);
is_emptyn($var0C);

?>