Foreach & for performance test

readme.md

corresponding blog post

https://janw.me/2019/for-foreach-performance

looptest.php

<?php
echo '<pre>';

$test_array = array();
for ( $i = 0; $i <= 10000; $i ++ ) {
	$test_array[] = [
		'index'   => $i,
		'include' => ( $i % 3 === 0 ) ? true : false,
	];
}

$start         = microtime( true );
$test_function = function ( $test_array ) {

	$filtered_array = [];
	foreach ( $test_array as $item ) {
		if ( true === $item['include'] ) {
			$filtered_array[] = $item;
		}
	}

	return $filtered_array;

};
for ( $i = 0; $i <= 5000; $i ++ ) {
	call_user_func( $test_function, $test_array );
}
echo microtime( true ) - $start . "sec Loop: foreach traditional<br/>";


$start         = microtime( true );
$test_function = function ( $test_array ) {

	foreach ( $test_array as $key => $item ) {
		if ( true === $item['include'] ) {
			unset( $test_array[ $key ] );
		}
	}

	return $test_array;

};
for ( $i = 0; $i <= 5000; $i ++ ) {
	call_user_func( $test_function, $test_array );
}
echo microtime( true ) - $start . "sec Loop: foreach unset key<br/>";


$start         = microtime( true );
$test_function = function ( $test_array ) {

	foreach ( $test_array as $key => &$item ) {
		if ( true === $item['include'] ) {
			unset( $test_array[ $key ] );
		}
	}

	return $test_array;

};
for ( $i = 0; $i <= 5000; $i ++ ) {
	call_user_func( $test_function, $test_array );
}
echo microtime( true ) - $start . "sec Loop: foreach &unset key<br/>";


$start         = microtime( true );
$test_function = function ( $test_array ) {

	$filtered_array = [];
	foreach ( $test_array as &$item ) {
		if ( true === $item['include'] ) {
			$filtered_array[] = $item;
		}
	}

	return $filtered_array;

};
for ( $i = 0; $i <= 5000; $i ++ ) {
	call_user_func( $test_function, $test_array );
}
echo microtime( true ) - $start . "sec Loop: foreach &traditional<br/>";


$start         = microtime( true );
$test_function = function ( $test_array ) {

	$length = count( $test_array );
	for ( $i = 0; $i < $length; $i ++ ) {
		if ( true === $test_array[ $i ]['include'] ) {
			unset( $test_array[ $i ] );
		}
	}

	return $test_array;

};
for ( $i = 0; $i <= 5000; $i ++ ) {
	call_user_func( $test_function, $test_array );
}
echo microtime( true ) - $start . "sec Loop: for<br/>";


echo '</pre>';
var_dump( phpversion() );

looptestbonus.php

<?php
echo '<pre>';

$test_array = array();
for ( $i = 0; $i <= 10000; $i ++ ) {
	$test_array[] = [
		'index'   => $i,
		'include' => ( $i % 3 === 0 ) ? true : false,
	];
}

$start         = microtime( true );
$test_function = function ( $test_array ) {

	$filtered_array = [];
	foreach ( $test_array as $item ) {
		if ( true === $item['include'] ) {
			$item['index'] ++;
		}
		$filtered_array[] = $item;
	}

	return $filtered_array;

};
for ( $i = 0; $i <= 7500; $i ++ ) {
	call_user_func( $test_function, $test_array );
}
echo microtime( true ) - $start . "sec Loop: foreach traditional<br/>";


$start         = microtime( true );
$test_function = function ( $test_array ) {

	foreach ( $test_array as $key => $item ) {
		if ( true === $item['include'] ) {
			$test_array[ $key ]['index'] ++;
		}
	}

	return $test_array;

};
for ( $i = 0; $i <= 7500; $i ++ ) {
	call_user_func( $test_function, $test_array );
}
echo microtime( true ) - $start . "sec Loop: foreach unset key<br/>";


$start         = microtime( true );
$test_function = function ( $test_array ) {

	foreach ( $test_array as $key => &$item ) {
		if ( true === $item['include'] ) {
			$item['index'] ++;
		}
	}

	return $test_array;

};
for ( $i = 0; $i <= 7500; $i ++ ) {
	call_user_func( $test_function, $test_array );
}
echo microtime( true ) - $start . "sec Loop: foreach traditional by reference<br/>";


$start         = microtime( true );
$test_function = function ( $test_array ) {

	$length = count( $test_array );
	for ( $i = 0; $i < $length; $i ++ ) {
		if ( true === $test_array[ $i ]['include'] ) {
			$test_array[ $i ]['index'] ++;
		}
	}

	return $test_array;

};
for ( $i = 0; $i <= 7500; $i ++ ) {
	call_user_func( $test_function, $test_array );
}
echo microtime( true ) - $start . "sec Loop: for<br/>";


echo '</pre>';
var_dump( phpversion() );