PHP data types

PHP data types

Data types specify the size and type of values that can be stored.
Variable does not need to be declared ITS DATA TYPE adding a value to it.
PHP is a Loosely Typed Language so here no need to define data type.
To check only data type use gettype( ) function.
To check value, data type and size use var_dump( ) function.
for eg : variable contains integer, float, and string value

<?php $num=100; $fnum=100.0; $str="Hello"; var_dump($num,$fnum,$str); ?>

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<?php $num=100; $fnum=100.0; $str="Hello"; var_dump($num,$fnum,$str); ?>

Output
int(100) float(100) string(5) “Hello”

In the above example
declare three variable $num , $fnum , $str.
$num hold value=”100″. (contain integer value).
$fnum hold value=100.0 (contain float value).
$str hold value=”Hello” (contain string value).

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Data types in PHP

There are 3 types of DATA TYPE

1. Scalar(predefined)
2. Compound(user-defined)
3. Special type

Scalar(It holds only single value)

1. Integer
2. Float/double
3. String
4. Boolean

Integer Data type

Integer means numeric data types. A whole number with no fractional component.
Integer may be less than greater than or equal to zero.
The size of an integer is platform-dependent, although a maximum value of about two billion is the usual value (that’s 32 bits signed). 64-bit platforms usually have a maximum value of about 9E18, except for Windows, which is always 32 bit
Integer value should be between -2,147,483,648 and 2,147,483,647

<?php $num=100; var_dump($num); ?>

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<?php $num=100; var_dump($num); ?>

Output
int(100)

In the above example
$num hold value=100. pass this variable with echo statement to print the value:

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Float/double Data type

It is also called numeric data types.A number with a fractional component.

<?php $num=100.0; var_dump($num); ?>

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<?php $num=100.0; var_dump($num); ?>

Output
float(100)

$num hold value=100.0. pass $num inside echo statement to display the output.

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String Data type

Non numeric data type
String can hold letters,numbers and special characters.
String value must be enclosed eighter in single quotes or double quotes.

<?php $str="Welcome user"; $str1='how r you?'; $str2="@"; var_dump($str); var_dump($str1); var_dump($str2); ?>

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<?php $str="Welcome user"; $str1='how r you?'; $str2="@"; var_dump($str); var_dump($str1); var_dump($str2); ?>

Output
string(12) “Welcome user” string(10) “how r you?” string(1) “@”

In the above example
We create three variable to hold three string values.
To display the output pass all three variables with echo output will display.

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Boolean Data type

Boolean are the simplest data type.Like a switch that has only two states ON means true(1) and OFF means false(0).

<?php $true=true; $false=false; var_dump($true,$false); ?>

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<?php    $true=true;    $false=false;    var_dump($true,$false); ?>

Output
bool(true) bool(false)

In the above example
declare variable $true hold value=true, variable($false) hold value=false.
Now check the datatype using var_dump( ) function.
Output will in boolean form: bool(true) bool(false)

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Compound(Multiple values in single variable)

1. Array
2. Object

Array Data type

<?php $arr=array(10,20,30,40,50); var_dump($arr); ?>

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<?php $arr=array(10,20,30,40,50); var_dump($arr); ?>

Output
array(5) { [0]=> int(10) [1]=> int(20) [2]=> int(30) [3]=> int(40) [4]=> int(50) }

In the above example
Variable( $arr) hold values an array . Now we want to print the first element of an array.
Then we pass variable($arr) name with index value[0], fetch the first element corresponding to the index value. Output will 10

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Object Data type

<?php class Demo { public function show() { echo "This is show method<br/>"; } } $obj= new Demo(); //$obj->show(); //$obj->show(); var_dump($obj); ?>

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<?php class Demo { public function show() { echo "This is show method<br/>"; } } $obj= new Demo(); //$obj->show(); //$obj->show(); var_dump($obj); ?>

Output
object(Demo)#1 (0) { }

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Special Data types

1. Null
2. Resource

Null Data type

The special Data type “NULL” represents a variable with no value.

<?php $blank=null; var_dump($blank); ?>

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<?php $blank=null;          var_dump($blank); ?>

Output
NULL

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Resource Data Type

The special resource type is not an actual data type. It is the storing of a reference to functions and resources external to PHP.
A common example of using the resource data type is a database call.
for eg:

<?php $con = mysqli_connect("localhost","root","","users"); ?>

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<?php $con = mysqli_connect("localhost","root","","users"); ?>

The function will return a resource type data to be stored into $con variable.

Some Predefine functions to Check data type

=> is_int( ) : Check given value is integer or not
=> is_float( ) : Check given value is float or not
=> is_numeric( ) : Check given value is either integer or float
=> is_string( ) : Check given value is string or not
=> is_bool( ) : Check given value is Boolean or not
=> is_array( ) : Check given value is array or not
=> is_object( ) : Check given value is object or not
=> is_null( ) : Check given value is null or not
Check if given variable holds a integer type of value then print the sum otherwise show error message)

<?php $x = 1000; $y = 500; if(is_int($x) && is_int($y)) { $sum = $x + $y; echo "sum = ".$sum; } else { echo "both number must be integer"; } ?>

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<?php          $x = 1000;          $y = 500;          if(is_int($x) && is_int($y))          {        $sum = $x + $y;        echo "sum = ".$sum;          }        else        {        echo "both number must be integer";          } ?>

Output
sum = 1500

In the above example
Create two variable $x hold value=100, $y hold value=500, now execute if..else condition.
We pass is_int( ) function inside if condition, to check the value is integer or not , if yes statement is execute and print the sum of two values. if not else statement is execute show an error message.