Data Types in PHP
PHP supports
eight primitive data types to construct variables. The data types supported by
PHP are:
Integers
- Integers can be specified in either decimal, hexadecimal, octal, or binary notation. Integers can be optionally be preceded with +/- signs
- To use octal notation, precede the number with 0
- To use hexadecimal notation, precede the number with Ox
- To use binary notation, precede the number with Ob
Note: Binary
integer literals are only available since PHP 5.4.0.
Example:
<?php
$a = 1234; //
decimal number
$a = -123; // a
negative number $a = 0123; // octal number (equivalent to 83 decimal)
$a = Ox1A; //
hexadecimal number (equivalent to 26 decimal)
?>
Doubles
- Doubles are floating point numbers. Doubles are also known as floats or real numbers
Example:
<?php
$a = 1.234;
$b = 1.2e3;
$c = 7e-10;
?>
Booleans
- Booleans can have only either of the two values, TRUE or FALSE
Example:
<?php
$t=date("H");
if
($t<"18")//$t<"18" can either be TRUE or FALSE
depending on time
{
echo "Have a
good day!";
}
else
{
echo "Have a
good night!";
}
?>
NULL
- NULL is a special type that has only one value NULL
Example:
<?php
$var = NULL;
?>
Strings
- Strings are sequence of characters. The can be denoted using either double quotes or single quotes.
Example:
<?php
$txt="Hello
world!";
echo $txt;
$my_name =
'Raju';
?>
Arrays
- Arrays are named and indexed collections of other data types.
Example:
<?php
$names=array("raju","ravi","pavan");
echo "My
name is: " . $names[0] . ", " ."</br>"."My
friends' names are: ". $names[1] . " and " . $names[2] .
".";
?>
Objects
- Objects are instances of programmer-defined classes and can package data types and functions that are specific to a class. 9 An Object of a class is created using the new statement.
Example:
<?php
class Myclass
{
function display()
{
echo
"welcome to object creation";
}
}
$one = new
Myclass;
$one->display();
?>
Resources
- Resources are special variables that hold references to resources that are external to PHP.
Example:
fbsql_db_query()
//Selects a database and executes a query on it.
ftp_connect()
//opens an FTP connection to the specified host .
imap_open()
//Open an IMAP stream to a mailbox
dba_popen()
//establishes a persistent database instance for path with //mode using handler
imagerotate()
//Rotate an image with a given angle
