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.
Eg i (variable contains integer, float, and string value)
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).

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
Integer means numeric data types. A whole number with no fractional component.
Integer may be less than greater than or equal to zero.
Eg ii
  echo $num;
 Output : 100
In the above example
$num hold value=100. pass this variable with echo statement to print the value:
2 Float
It is also called numeric data types.A number with a fractional component.
Eg iii
  echo $num;
 Output : 100.0
$num hold value=100.0. pass $num inside echo statement to display the output.
3 String
Non numeric data type
String can hold letters,numbers and special characters.
String value must be enclosed eighter in single quotes or double quotes.
Eg iv
  $str="Welcome user";
  $str1='how r you?';
  echo $str;
  echo $str1;
  echo $str2;
  Output : Welcome user
     how r you?
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.

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

   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)

Compound(Multiple values in single variable)

  1. Array
  2. Object
Eg vi (Example of array)
  echo $arr[0];  
  Output : 10
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

Eg vi (Example of object)
  class Demo()
   public function show()
    echo "This is show method<br/>";
  $obj= new Demo();
  Output : This is show method
           This is show method

Special(2 types)

  1. Null
  2. Resource
Eg vii ( for null )
  Output : NULL

Predefine function to Check data types

=> 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

Eg viii ( Check if given variable holds a integer type of value then print the sum otherwise show error message)
        $x = 1000;
        $y = 500;
        if(is_int($x) && is_int($y))
        $sum = $x + $y;
        echo "sum = ".$sum;
       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.


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