https://php1st.com/1392/

array_push()とarray[]の実行速度比較

$ time php test01.php 

real	0m0.213s
user	0m0.063s
sys	0m0.039s
$ time php test02.php 

real	0m0.083s
user	0m0.050s
sys	0m0.020s

# ちなみにphp7.1の実行結果
$ time php test01.php

real	0m0.291s
user	0m0.105s
sys	0m0.036s
$ time php test02.php 

real	0m0.059s
user	0m0.031s
sys	0m0.014s

test01.php

<?php
$array = array();
for ($i = 0; $i < 100000; $i++) {
    array_push($array, $i);
}

test02.php

<?php
$array = array();
for ($i = 0; $i < 100000; $i++) {
    $array[] = $i;
}