PHP Declare Statement

Last update on May 28 2022 12:33:32 (UTC/GMT +8 hours)

Description

In PHP declare construct is used to set execution directives for a block of code. At present two directives are recognized ticks and encoding.

Syntax:

declare (directive) statement

The following table describes two directives currently supported.

Directive	Description
ticks	A tick is an event. While the format of specifying the tick directive is tick=N, where N is an integer. The tick event occurs for every N statements (following the declare). Usually, condition expressions and argument expressions are excluded from being executed. Register_tick_function() is used to specify each event(s) that occur on each tick. Remember that this directive is deprecated in PHP5.3.
encoding	The encoding directive specifies a script's encoding. Usage of this detective is decal re(encoding="EncodingType") where EncodingType is a encoding type like ISO-8859-1. This directive can be used only if PHP is compiled with --enable-zend-multibyte. You can use phpinfo() to know whether a PHP installation

Directive

Description

ticks

A tick is an event. While the format of specifying the tick directive is tick=N, where N is an integer. The tick event occurs for every N statements (following the declare). Usually, condition expressions and argument expressions are excluded from being executed. Register_tick_function() is used to specify each event(s) that occur on each tick. Remember that this directive is deprecated in PHP5.3.

encoding

The encoding directive specifies a script's encoding. Usage of this detective is decal re(encoding="EncodingType") where EncodingType is a encoding type like ISO-8859-1. This directive can be used only if PHP is compiled with --enable-zend-multibyte. You can use phpinfo() to know whether a PHP installation

Example of PHP declare statement using tick directive

<?php
declare(ticks=5);
// the following function is called on each tick event
function w3r_tick()
{
echo "w3r_tick() called<br>";
}
register_tick_function('w3r_tick');
$a = 5;
if ($a > 0)
{
$a += 2;
print($a);
}
?>

View the example in the browser

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PHP: Tips of the Day

How to Sort Multi-dimensional Array by Value?

Try a usort, If you are still on PHP 5.2 or earlier, you'll have to define a sorting function first:

Example:

function sortByOrder($a, $b) {
    return $a['order'] - $b['order'];
}

usort($myArray, 'sortByOrder');

Starting in PHP 5.3, you can use an anonymous function:

usort($myArray, function($a, $b) {
    return $a['order'] - $b['order'];
});

And finally with PHP 7 you can use the spaceship operator:

usort($myArray, function($a, $b) {
    return $a['order'] <=> $b['order'];
});

To extend this to multi-dimensional sorting, reference the second/third sorting elements if the first is zero - best explained below. You can also use this for sorting on sub-elements.

usort($myArray, function($a, $b) {
    $retval = $a['order'] <=> $b['order'];
    if ($retval == 0) {
        $retval = $a['suborder'] <=> $b['suborder'];
        if ($retval == 0) {
            $retval = $a['details']['subsuborder'] <=> $b['details']['subsuborder'];
        }
    }
    return $retval;
});

If you need to retain key associations, use uasort() - see comparison of array sorting functions in the manual

Ref : https://bit.ly/3i77vCC