в 10:37, 26 мая 2010

2010-05-26T10:37:26Z

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2010-05-26T07:05:40Z

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==$b is assigned a copy of $a, and in the second part, $b is assigned a reference to $a.==



<source lang="html4strict">

<?php
$a = 5;
$b = $a;
$a = 7;
echo "\$a = $a and \$b = $b\n";

$a = 5;
$b = &$a;
$a = 7;
echo "\$a = $a and \$b = $b\n";
?>

</source>

==Create a reference to a variable with the name of the constant"s value.==



<source lang="html4strict">

<?php
define("CONST_A", "test");
${CONST_A} = 27;
echo "\$test = $test\n";
?>

</source>

==Only named variables may be assigned by reference.==



<source lang="html4strict">

<?php
$foo = 25;
$bar = &$foo; // This is a valid assignment.

function test() {
return 25;
}
$bar = &test(); // Invalid.
?>

</source>

==& operator creates a reference==



<source lang="html4strict">

<?php
$a = 5;
$b = $a;
$a = 7;
echo "\$a = $a and \$b = $b\n";
$a = 5;
$b = &$a;
$a = 7;
echo "\$a = $a and \$b = $b\n";
?>

</source>

==Passing arrays by reference==



<source lang="html4strict">

<?
function load_member_data($ID, &$member) {
$member["Name"] = "Bob";
return true;
}
$ID = 1;
$result = load_member_data($ID, $member);
if ($result) {
print "Member {$member["Name"]} loaded successfully.\n";
} else {
print "Failed to load member #$ID.\n";
}
?>

</source>

==Passing by Reference in PHP==



<source lang="html4strict">

<?php
function reference_test($var, &$result, &$result2) {
$result = "This is return value #1";
$result2 = "You entered $var as your parameter";
return 42;
}
$res = reference_test(10, &$res1, &$res2);
echo "The value of \$res is "$res"<BR>";
echo "The value of \$res1 is "$res1"<BR>";
echo "The value of \$res2 is "$res2"<BR>";
?>

</source>

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PHP/Language Basics/Variable Reference - История изменений

в 10:37, 26 мая 2010

Admin: 1 версия