PHP Variable

PHP Variable 

<?php 

//Remember that PHP variable names are case-sensitive!

//In PHP, variables can be declared anywhere in the script.

$var1 = "myvariable 1";

echo "This is $var1!";

echo "<br>";

echo "This is ".$var1."!";

echo "<br>";

// Print the sum of two number using variable

$x = 3;

$y = 2;

echo $x + $y;

echo "<br>";

/*

PHP has three different variable scopes:

local

global

static

 Global scope :

A variable declared outside a function has a GLOBAL SCOPE and can only be accessed outside a function 

*/

$a = 5; // global scope

function myFun() {

//using 'a' inside this function will generate an error

echo "<p> variable a inside function is: $a </p>";

}

myFun();

echo "<p> variable a outside function is: $a </p>"; 

/*

Local scope :

A variable declared within a function has a LOCAL SCOPE and can only be accessed within that function

*/

function myFun2() {

$b = 6; // local scope

echo "<p> variable b inside function is: $b </p>";

}

myFun2();

//using 'b' outside the function will generate an error

echo "<p> variable b outside function is: $b </p>";

/*

You can have local variables with the same name in different functions, because local variables are only recognized by the function in which they are declared.

*/

// PHP Global keyword

/*

The global keyword is used to access a global variable from within a function.

To do this, use the global keyword before the variables (inside the function)

*/

$c = 1;

$d = 7;

function myTest() {

global $c, $d;

$d = $c + $d;

}

myTest();

echo $d; // output 8

echo "<br>";

/*

PHP also stores all global variables in an array called $GLOBALS[index]. The index holds the name of the variable. This array is also accessible from within functions and can be used to update global variables directly.

*/

$x1 = 5;

$y1 = 10;

function myTest3() {

  $GLOBALS['y1'] = $GLOBALS['x1'] + $GLOBALS['y1'];

}

myTest3();

echo $y1; // outputs 15

echo "<br>";

/*

PHP The static Keyword

Normally, when a function is completed/executed, all of its variables are deleted. However, sometimes we want a local variable NOT to be deleted. We need it for a further job.

To do this, use the static keyword when you first declare the variable:

*/

function myTest4() {

  static $x2 = 0;

  echo $x2;

  $x2++;

}

myTest4();

echo "<br>";

myTest4();

echo "<br>";

myTest4();

echo "<br>";

myTest4();

echo "<br>";

?>

<?php 

//Remember that PHP variable names are case-sensitive!

//In PHP, variables can be declared anywhere in the script.

$var1 = "myvariable 1";

echo "This is $var1!";

echo "<br>";

echo "This is ".$var1."!";

echo "<br>";

// Print the sum of two number using variable

$x = 3;

$y = 2;

echo $x + $y;

echo "<br>";

/*

PHP has three different variable scopes:

local

global

static

 Global scope :

A variable declared outside a function has a GLOBAL SCOPE and can only be accessed outside a function 

*/

$a = 5; // global scope

function myFun() {

    //using 'a' inside this function will generate an error

    echo "<p> variable a inside function is: $a </p>";

}

myFun();

echo "<p> variable a outside function is: $a </p>"; 

/*

Local scope :

A variable declared within a function has a LOCAL SCOPE and can only be accessed within that function

*/

function myFun2() {

    $b = 6; // local scope

    echo "<p> variable b inside function is: $b </p>";

}

myFun2();

//using 'b' outside the function will generate an error

echo "<p> variable b outside function is: $b </p>";

/*

You can have local variables with the same name in different functions, because local variables are only recognized by the function in which they are declared.

*/

// PHP Global keyword

/*

The global keyword is used to access a global variable from within a function.

To do this, use the global keyword before the variables (inside the function)

*/

$c = 1;

$d = 7;

function myTest() {

    global $c, $d;

    $d = $c + $d;

}

myTest();

echo $d; // output 8

echo "<br>";

/*

PHP also stores all global variables in an array called $GLOBALS[index]. The index holds the name of the variable. This array is also accessible from within functions and can be used to update global variables directly.

*/

$x1 = 5;

$y1 = 10;

function myTest3() {

  $GLOBALS['y1'] = $GLOBALS['x1'] + $GLOBALS['y1'];

}

myTest3();

echo $y1; // outputs 15

echo "<br>";

/*

PHP The static Keyword

Normally, when a function is completed/executed, all of its variables are deleted. However, sometimes we want a local variable NOT to be deleted. We need it for a further job.

To do this, use the static keyword when you first declare the variable:

*/

function myTest4() {

  static $x2 = 0;

  echo $x2;

  $x2++;

}

myTest4();

echo "<br>";

myTest4();

echo "<br>";

myTest4();

echo "<br>";

myTest4();

echo "<br>";

?>