This function check whether a variable is empty or not.
Note : - Return false if variable has a non_empty and non-zero value. Return true if variable has empty or zero.
Return Type:- bool
<?php
$var = 30;
if (empty($var))
{
echo "Varible is empty";
}
else
{
echo "Varible is not empty";
}
?>
Output:-
Varible is not empty
This function check whether variable exists or not. Return True if variable exists otherwise return False.
Note : - isset function is very usefull for check $_Post['btnsubmit'], $_Get['btnsubmit'] etc variable.
Return Type:- bool
<?php
$var = 30;
if (isset($var))
{
echo "Varible is exist";
}
else
{
echo "Varible is not exist";
}
?>
Output :-
Varible is exist
This function destroy variables.
Note :- You can use unset function to destroy session varaibles.
Return Type :- void
<?php
$var = 30;
echo $var;
unset($var);
echo $var;
?>
Output :-
30
This function display information about variable.
Return Type :- bool
<?php
$my_array = array(5,6,7,8);
print_r($my_array);
?>
Output :-
Array ( [0] => 5 [1] => 6 [2] => 7 [3] => 8 )
This function returns the integer value of the variable.
Return Type :- int
<?php
echo intval(45.67);
echo "<br>";
echo intval(-67.45);
?>
Output :
45
-67
This function returns the type of variable.
Return Type :- string
<?php
$x="welcome";
$y=56;
$z=56.34;
echo gettype($x);
echo "<br>";
echo gettype($y);
echo "<br>";
echo gettype($z);
?>
Output :
string
integer
double
This function returns convert variable datatype.
Return Type :- bool
<?php
$x="welcome";
$y=56;
$z=56.34;
settype($x,"integer");
echo gettype($x);
echo "<br>";
settype($y,"boolean");
echo gettype($y);
echo "<br>";
settype($z,"double");
echo gettype($z);
?>
Output :
integer
boolean
double
This function convert a value of the variable to the string.
Return Type :- string
Example :-
<?php
$num=5;
$str=strval($num);
echo gettype($num)."<br>";
echo gettype($str);
?>
Output :-
integer
string
This function provide us dumps information of variable.
Return Type :- void
Example :-
<?php
$x="This is test string";
$a = array(34, 62, array("sun", "mon", "tue"));
var_dump($x);
var_dump($a);
?>
Output :-
string 'This is test string' (length=19)
array
0 => int 34
1 => int 62
2 =>
array
0 => string 'sun' (length=3)
1 => string 'mon' (length=3)
2 => string 'tue' (length=3)