if we use gettype() before initializinf any variable it give NULL
for eg.
<?php
$foo;
echo gettype($foo);
?>
it will show
NULL
Types
Table of Contents
add a note
User Contributed Notes 4 notes
shahnaz khan ¶
8 years ago
shaharia dot azam at gmail dot com ¶
5 months ago
<?php
/* delcare few variable to check their data type */
$intVar = 10; //Integar variable
$floatVar = 2.49; //Float type aka Double
$stringVar = "There are 8 data types in PHP"; // String
$arrayVar = array(
'Boolean',
'Integar',
'Float aka Double',
'String', 'Array',
'Object',
'Resource',
'Null'
); // Array type
$booleanVar = true; // Boolean type
// Make an empty class to check object type
class obj{
}
$objectVar = new obj();
// To check resource type
$resource = mysql_connect();
// Null value
$nullVar = null;
// output the data type of each variable
echo gettype($intVar);
echo "\n";
echo gettype($floatVar);
echo "\n";
echo gettype($stringVar);
echo "\n";
echo gettype($arrayVar);
echo "\n";
echo gettype($booleanVar);
echo "\n";
echo gettype($objectVar);
echo "\n";
echo gettype($resource);
echo "\n";
echo gettype($nullVar);
echo "\n";
arjini at gmail dot com ¶
8 years ago
Note that you can chain type castng:
var_dump((string)(int)false); //string(1) "0"
Jeffrey ¶
5 years ago
The Object (compound) Type
Like every programming language, PHP offers the usual basic primitive types which can hold only one piece of data at a time (scalar). I am particularly fond of the "object" type (compound) because that allows me to group many basic PHP types together, and I can name it anything I want.
<?php
class Person
{
$firstName; // a PHP String
$middleName; // a PHP String
$lastName; // a PHP String
$age; // a PHP Integer
$hasDriversLicense; // a PHP Boolean
}
?>
Here, I have grouped several basic PHP types together, (3) Strings, (1) Integer, and (1) Boolean... then I named that group "Person". Since I used the proper syntax to do so, this code is pure PHP, which means that if you run this code, you would have an extra PHP "type" available to you in your scripts, like so:
<?php
$myAge = 16; // a PHP Integer - always available
$yourAge = 15.5; // a PHP Float - always available
$hasHair = true; // a PHP Boolean - always available
$greeting = "Hello World!" // a PHP String - always available
$person = new Person(); // a PHP Person - available NOW!
?>
You can make your own object types and have PHP execute it as if it were part of the PHP language itself. See more on classes and objects in this manual at: http://www.php.net/manual/en/language.oop5.php
