PHP Data Types
PHP data types are used to
hold different types of data or values. PHP supports 8 primitive data types
that can be categorized further in 3 types:
1.
Scalar
Types (predefined)
2.
Compound
Types (user-defined)
3.
Special
Types
Scalar Types
It holds only single value.
There are 4 scalar data types in PHP.
i.
boolean
ii.
integer
iii.
float
iv.
string
Compound Types
It can hold multiple
values. There are 2 compound data types in PHP.
i.
array
ii.
object
Special Types
There are 2 special data
types:
i.
resource
ii. NULL
PHP Boolean
Booleans are the simplest
data type works like switch. It holds only two values: TRUE (1) or FALSE
(0). It is often used with conditional statements. If the condition is
correct, it returns TRUE otherwise FALSE.
Example:
<?php if (TRUE) echo "This condition is TRUE."; if (FALSE) echo "This condition is FALSE."; ?>
|
Output:
This condition is TRUE.
Explanation Of
CODE:
·
The first if statement:
if (TRUE)
echo "This condition is TRUE.";
In this case, the condition inside the parentheses is
TRUE. Since TRUE is always true in PHP, the code inside the corresponding block
will be executed. Therefore, the string "This condition is TRUE."
will be echoed.
·
The second if statement:
if (FALSE)
echo "This condition is FALSE.";
In this case, the condition inside the parentheses is
FALSE. Since FALSE is always false in PHP, the code inside the corresponding
block will not be executed. Therefore, the string "This condition is
FALSE." will not be echoed.
So, when you run this code, only the output
of the first if statement will be displayed:
This condition is TRUE.
PHP Integer
Integer means numeric data
with a negative or positive sign. It holds only whole numbers, i.e., numbers
without fractional part or decimal points.
Rules for integer:
1.
An
integer can be either positive or negative.
2.
An integer
must not contain decimal point.
3.
Integer
can be decimal (base 10), octal (base 8), or hexadecimal (base 16).
4.
The range
of an integer must be lie between 2,147,483,648 and 2,147,483,647 i.e., -2^31
to 2^31.
Example:
<?php $dec1 = 34; $oct1 = 0243; $hexa1 = 0x45; echo "Decimal number: " .$dec1. "</br>"; echo "Octal number: " .$oct1. "</br>"; echo "HexaDecimal number: " .$hexa1. "</br>"; ?>
|
Output:
Decimal number: 34
Octal number: 163
HexaDecimal number: 69
Explanation Of
CODE:
·
$oct1 = 0243;: This variable is assigned the octal value 243. Octal
numbers in PHP start with a leading zero.
·
$hexa1 = 0x45;: This variable is assigned the hexadecimal value 45.
Hexadecimal numbers in PHP start with "0x" or "0X".
·
The echo statements then display these values with corresponding labels:
·
echo "Decimal number: " . $dec1 . "</br>";:
Outputs "Decimal number: 34" on the webpage.
·
echo "Octal number: " . $oct1 . "</br>";:
Outputs "Octal number: 243" on the webpage.
·
echo "Hexadecimal number: " . $hexa1 .
"</br>";: Outputs "Hexadecimal number: 69" on the
webpage.
·
When you run this code, you will see the representation of the decimal,
octal, and hexadecimal numbers on the webpage.
PHP Float
A floating-point number is
a number with a decimal point. Unlike integer, it can hold numbers with a
fractional or decimal point, including a negative or positive sign.
Example:
<?php $n1 = 19.34; $n2 = 54.472; $sum = $n1 + $n2; echo "Addition of floating numbers: " .$sum; ?>
|
Output:
Addition of floating numbers: 73.812
Explanation of
CODE:
·
$n1 = 19.34;:
This variable is assigned
the floating-point value 19.34.
·
$n2 = 54.472;:
This variable is assigned
the floating-point value 54.472.
·
$sum = $n1 + $n2;:
This line calculates the
sum of the two floating-point numbers and stores the result in the variable
$sum.
·
echo "Addition of floating numbers: " . $sum;:
The echo statement outputs
the text "Addition of floating numbers: " concatenated with the value
of $sum.
This will display the
result of the addition on the webpage.
PHP String
A string is a non-numeric
data type. It holds letters or any alphabets, numbers, and even special
characters.
String values must be
enclosed either within single quotes or in double
quotes. But both are treated differently. To clarify this, see the
example below:
Example:
<?php
$company = "Javatpoint";
//both single and double quote statements will treat different
echo "Hello $company";
echo "</br>";
echo 'Hello $company';
?>
Output:
Hello Javatpoint
Hello $company
Explanation of CODE:
·
$company = "Javatpoint";:
This line
assigns the string "Javatpoint" to the variable $company.
·
echo "Hello $company";:
In this line,
the double-quoted string allows the variable $company to be directly
interpolated within the string. This means that the value of the variable is
inserted into the string when it is echoed. The output of this line will be:
Hello Javatpoint.
·
echo "</br>";:
This line
outputs an HTML line break (<br>), creating a new line.
·
echo 'Hello $company';:
In this line, the
single-quoted string treats everything between the single quotes as a literal
string. The variable $company is not interpolated, and the output will be:
Hello $company.
PHP Array
An array is a compound data
type. It can store multiple values of same data type in a single variable.
Example:
<?php
$bikes = array ("Royal Enfield", "Yamaha", "KTM");
var_dump($bikes); //the var_dump() function returns the datatype and values
echo "</br>";
echo "Array Element1: $bikes[0] </br>";
echo "Array Element2: $bikes[1] </br>";
echo "Array Element3: $bikes[2] </br>";
?>
Output:
array(3) { [0]=> string(13) "Royal Enfield" [1]=> string(6) "Yamaha" [2]=> string(3) "KTM" }
Array Element1: Royal Enfield
Array Element2: Yamaha
Array Element3: KTM
Explanation of CODE
·
$bikes = array("Royal Enfield", "Yamaha",
"KTM");:
This line creates an array
named $bikes with three elements, each representing a brand of motorcycle.
·
var_dump($bikes);:
The var_dump() function is
used to display the datatype and values of the array. The output shows that
it's an array with three elements, and it provides information about the type
and length of each string element.
·
echo "</br>";:
This line outputs an HTML
line break (<br>), creating a new line in the display.
·
echo "Array Element1: $bikes[0] </br>";, echo
"Array Element2: $bikes[1] </br>";, echo "Array Element3:
$bikes[2] </br>";:
These lines access
individual elements of the array and echo them. The output shows the values of
each element.
PHP object
Objects are the instances
of user-defined classes that can store both values and functions. They must be
explicitly declared.
Example:
<?php
class bike {
function model() {
$model_name = "Royal Enfield";
echo "Bike Model: " .$model_name;
}
}
$obj = new bike();
$obj -> model();
?>
Output:
Bike Model: Royal Enfield
Explaination Of CODE:
·
class bike { ... }:
This declares a class named
bike. Inside the class, there is a method called model().
·
function model() { ... }:
This is the model() method
of the bike class. It contains a local variable $model_name set to "Royal
Enfield" and echoes the text "Bike Model: " concatenated with
the value of $model_name.
·
$obj = new bike();:
This line creates an
instance of the bike class and assigns it to the variable $obj. Now, $obj is an
object of the bike class.
·
$obj->model();:
This line calls the model()
method on the $obj object. As a result, "Bike Model: Royal Enfield"
will be echoed to the screen.
PHP Resource
Resources are not the exact
data type in PHP. Basically, these are used to store some function calls or
references to external PHP resources. For example -
a database call. It is an external resource.
Example:
<?php
// Open a file for reading
$fileHandle =
fopen("example.txt", "r");
// Check if the file handle
is a valid resource
if
(is_resource($fileHandle)) {
echo "File handle is a valid
resource.<br>";
// Reading and displaying the content of
the file
$content = fread($fileHandle,
filesize("example.txt"));
echo "File content:
$content<br>";
// Close the file handle
fclose($fileHandle);
} else {
echo "Failed to open the
file.<br>";
}
?>
Output:
·
suppose your file example.txt
contains the following content:
Hello, this is an example
file.
In this case, the output of
the program would be:
File handle is a valid
resource.
File content: Hello, this
is an example file.
·
If "example.txt" doesn't exist or cannot be opened for some
reason, the output might be:
Failed to open the file.
Explanation Of CODE:
·
fopen("example.txt", "r");:
This function opens the
file "example.txt" for reading and returns a file handle resource.
The resource is stored in the variable $fileHandle.
·
is_resource($fileHandle):
This function checks if
$fileHandle is a valid resource. If it is, the code proceeds to read the file
content.
·
fread($fileHandle, filesize("example.txt")):
This function reads the
content of the file associated with the file handle ($fileHandle). The file
size is determined using filesize("example.txt").
·
fclose($fileHandle);:
This function closes the
file handle when it's no longer needed.
PHP Null:
Null is a special data type
that has only one value: NULL. There is a convention of
writing it in capital letters as it is case sensitive.
The special type of data
type NULL defined a variable with no value.
Example:
<?php
$nl = NULL;
echo $nl; //it will not give any output
?>
Output:
No visible output
Explanation of CODE:
$nl =
NULL;:
This line
initializes a variable $nl and assigns it the value NULL. In PHP, NULL is a
special constant representing a variable with no value or no type.
echo
$nl;:
The echo
statement is used to output the value of the variable $nl. However, since the
value is NULL, it will not produce any visible output.