PHP/Language Basics/Variable Scope
Содержание
- 1 Defining Variable Scope
- 2 local variables
- 3 More Working with Variable Scope
- 4 Scope of a Variable
- 5 Use variable defined outside function
- 6 Variable Scope
- 7 Variable Scope: A Variable Declared Within a Function Is Unavailable Outside the Function
- 8 Variable scope: function
- 9 Variable Scope in Functions
- 10 Variables Defined Outside Functions Are Inaccessible from Within a Function by Default
Defining Variable Scope
<?php
$a = 7;
function test() {
$a = 20;
}
test();
echo "\$a = $a\n";
?>
local variables
<?php
$x = 4;
function assignx () {
$x = 0;
print "\ $x inside function is $x. <br>";
}
assignx();
print "\ $x outside of function is $x. <br>";
?>
More Working with Variable Scope
<?php
function getglobal() {
global $my_global;
echo "The value of \$foobar is "$foobar"<BR>";
}
$my_global = 20;
getglobal();
?>
Scope of a Variable
<?php
$a = "asdf";
function music (){
$a = "Music is great";
}
print $a;
?>
Use variable defined outside function
<?php
$ilike = "Rock";
function music(){
echo "I love listening to $ilike music!", "\n";
}
music();
?>
Variable Scope
<?php
$num;
function make_triple($arg)
{
global $num;
$num = $arg + $arg +$arg;
thrice();
}
function thrice()
{
global $num;
echo("The value is $num");
}
?>
<html>
<head>
<title>Variable Scope</title>
</head>
<body>
<h3> <?php make_triple(4); ?> </h3>
</body>
</html>
<html>
<head>
<title>Local Variable Unavailable Outside a Function</title>
</head>
<body>
<div>
<?php
function test() {
$testvariable = "this is a test variable";
}
print "test variable: $testvariable<br/>";
?>
</div>
</body>
</html>
Variable scope: function
<?php
increment ();
increment ();
increment ();
function increment () {
$a=0;
echo $a;
$a++;
}
?>
Variable Scope in Functions
function foo( ) {
$bar = "wombat";
}
$bar = "baz";
foo( );
print $bar;
Variables Defined Outside Functions Are Inaccessible from Within a Function by Default
<html>
<head>
<title>Variables Defined Outside Functions Are Inaccessible from Within a Function by Default</title>
</head>
<body>
<?php
$life = 42;
function meaningOfLife(){
print "The meaning of life is $life<br>";
}
meaningOfLife();
?>
</body>
</html>