Search Array : array_filter vs loop

user_608576 0
Viewed 15821

I am really new in PHP and need a suggestion about array search.

If I want to search for an element inside a multidimensional array, I can either use array_filter or I can loop through the array and see if an element matching my criteria is present.

I see both suggestion at many places. Which is faster? Below is a sample array.

Array ( 
  [0] => Array ( 
    [id] => 4e288306a74848.46724799
    [question] => Which city is capital of New York?
    [answers] => Array ( 
      [0] => Array ( 
        [id] => 4e288b637072c6.27436568 
        [answer] => New York 
        [question_id_fk] => 4e288306a74848.46724799 
        [correct] => 0 
      ) 
      [1] => Array ( 
        [id] => 4e288b63709a24.35955656 
        [answer] => Albany 
        [question_id_fk] => 4e288306a74848.46724799 
        [correct] => 1 
      ) 
    )
  )
)

I am searching like this.

$thisQuestion = array_filter($pollQuestions, function($q) {
  return questionId == $q["id"];
});
multidimensional-array arrays php
5 Answers

I've made a test script because I was a little skeptical ...how can an internal function be slower than a loop...

But actually it's true. Another interesting result is that php 7.4 is almost 10x faster than 7.2!

You can try yourself

<?php
/*** Results on my machine ***
php 7.2
array_filter: 2.5147440433502
foreach: 0.13733291625977
for i: 0.24090600013733

php 7.4
array_filter: 0.057109117507935
foreach: 0.021071910858154
for i: 0.027867078781128
**/

ini_set('memory_limit', '500M');
$data = range(0, 1000000);

// ARRAY FILTER
$start = microtime(true);
$newData = array_filter($data, function ($item) {
    return $item % 2;
});
$end = microtime(true);

echo "array_filter: ";
echo $end - $start . PHP_EOL;

// FOREACH
$start = microtime(true);
$newData = array();
foreach ($data as $item) {
    if ($item % 2) {
        $newData[] = $item;
    }
}
$end = microtime(true);

echo "foreach: ";
echo $end - $start . PHP_EOL;

// FOR
$start = microtime(true);
$newData = array();
$numItems = count($data);
for ($i = 0; $i < $numItems; $i++) {
    if ($data[$i] % 2) {
        $newData[] = $data[$i];
    }
}
$end = microtime(true);

echo "for i: ";
echo $end - $start . PHP_EOL;
user_38131170

I know it's an old question, but I'll give my two cents: for me, using a foreach loop was much faster than using array_filter. Using foreach, it took 1.4 seconds to perform a search by id, and using the filter it took 8.6 seconds.

user_35491770

From my own experience, foreach is faster. I think it has something to do with function call overhead, arguments check, copy to variable return instruction, etc.. When using a basic syntax, the parsed code is more likely to be closer to the compiled/interpreted bytecodes, have better optimization down the core.

The common rule is : anything is simplier, run faster (imply less check, less functionnality, as long as it has all you need)

user_5099160
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