PHP Quick Start Learning-4 (data type)

PHP 5Data Type

String (String), Integer (integer), float (floating-point), Boolean (Boolean), Array (array), Object (objects), null (null value).

PHP string

A string is a sequence of characters, just like "Hello world!".

You can put any text in single and double quotation marks:

<?  $x = "Hello world!" ; Echo $x ; Echo "<br>"$x = ' Hello world! ' ; Echo $x ;? >

PHP Integral type

An integer is a number that has no decimals.

Integer rule:

• Integers must have at least one number (0-9)
• Integers cannot contain commas or spaces
• Integers are no decimal points.
• Integers can be positive or negative
• Integer types can be specified in three formats: decimal, hexadecimal (prefixed with 0x), or octal (prefixed with 0).

In the following example we will test for different numbers. The PHP var_dump () function returns the data type and value of the variable:

<?PHP$x= 5985;Var_dump($x);Echo"<br>"; $x=-345;//Negative numberVar_dump($x);Echo"<br>"; $x= 0x8c;//Hexadecimal numberVar_dump($x);Echo"<br>";$x= 047;//octal numberVar_dump($x);?>

PHP floating Point type

A float is a number with a decimal point, or an exponential form.

In the following example we will test for different numbers. The PHP var_dump () function returns the data type and value of the variable

<?  $x = 10.365; Var_dump ($x); Echo "<br>"$x = 2.4e3; Var_dump ($x); Echo "<br>"$x = 8E-5; Var_dump ($x);? >

PHP Boolean type

The Boolean type can be TRUE or FALSE.

$x=true; $y=false;

Boolean is commonly used for conditional judgment, more tutorials on conditional control.

PHP arrays

An array can store multiple values in a variable.

An array is created in the following instance, and then the data type and value of the array are returned using the PHP Var_dump () function:

<?  $cars=array("Volvo", "BMW", "Toyota"); Var_dump ($cars);? >

PHP Object

Object data types can also be used to store data.

In PHP, the object must be declared.

First, you must declare the class object using the Class keyword. A class is a structure that can contain properties and methods.

Then we define the data type in the class and then use the data type in the instantiated class:

<? PHP class car{  var$color;   function Car ($color= "Green") {    $this$color;  }   function What_color () {    return$this,color;  }}? >

The PHP keyword in the above example is a pointer to the current object instance and does not point to any other object or class.

PHP NULL Value

A NULL value indicates that the variable has no value. Null is a value with a data type of NULL.

A null value indicates whether a variable is a null value. It can also be used to distinguish between null values and data nulls.

Variable data can be emptied by setting the value of the variable to NULL:

<? PHP $x= "Hello world!" ; $x=null; Var_dump ($x);? >

PHP Quick Start Learning-4 (data type)